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71.
PROSPECTS - Education is going through a period of crisis related to the SARS-CoV-2 pandemic that most probably will follow a continuum organized into distinct phases: emergency, recovery,...  相似文献   
72.
The purpose is to document the ongoing development of two schools in becoming professional learning communities and the effects of meaningful collaboration on teacher learning. The question that guides this research is: How does a school become a sustainable professional learning community? The theoretical framework is based on the work of Senge, Hord, Fullan, Hargreaves and Fink, and Stoll, McMahon and Thomas and includes the areas of professional learning community, change and sustainability. Finally, the study addresses the relationship between professional learning community and school culture. The methodology involves a qualitative case study approach designed to gain information regarding two emerging schools in their journeys toward developing learning community cultures. Findings reveal the stories of each school as they evolved as PLCs and the similarities and differences that emerged. Knowing that sustaining the culture of a PLC is complex, and not to be achieved without determination and growth, we look ahead at challenges to be addressed and further research to be conducted. Finally, we offer some concluding statements and attempt to relate findings to the literature on PLCs. The intent is to identify some of the intricacies in building cultures of learning for adults and students. As we have learned through these two stories, many things happen simultaneously, to greater or lesser degrees, at varying points in time over a period of years that seem to influence the development of a PLC. Such development seems so complex that to be able to describe discrete steps or stages is unlikely. Still we are beginning to see that some categories of activities and issues must be developed before others can emerge.  相似文献   
73.
The article examines a number of links between the metaphorical uses of the concept of metamorphosis in literature and the various changes of the meaning of the concept that took place at the beginning of the modern scientific age between the 17th and 19th centuries, a period during which the notion of metamorphosis resurfaced in conflict with evolutionist thinking. We present the extent to which the concept of animal metamorphosis, the object of multiple redefinitions over the course of this historical period, became the vector of a very strong metaphorical meaning, which emerged in the literature of the period and survives to this day in certain children’s storybooks belonging to what we term the genre of “realistic fiction”. We intend, from a pedagogical standpoint, to identify which specific attributes of these metaphors exist in those storybooks, and to gauge the extent to which those attributes contradict the scientific characteristics and fictional representations of the concept of metamorphosis.  相似文献   
74.
Know-how is a critical element of franchising, and its transfer is a key issue for franchisors and their staff. The aim of this paper was to analyse franchisees’ perceptions about know-how transfer in franchise networks. Findings of our qualitative empirical study show that franchisees seem to value the mechanisms used in their network, which include formalised processes (the operations manual, online tools), training (initial and ongoing) and social mechanisms (discovery sessions, meetings and committees). Only the effectiveness of on-field consultants is questioned, which leads to important managerial implications. At the theoretical level, the paper contributes to our understanding of franchise operations by providing a franchisee-centred model of how knowledge is created and disseminated in the networks.  相似文献   
75.
Olivier Bertrand   《Research Policy》2009,38(6):1021-1031
This paper investigates the causal effect of foreign acquisitions on the research and development (R&D) activities of domestic target firms over the period 1994–2004. Using accounting data on French innovative manufacturing firms, we implement appropriate difference-in-difference estimation techniques associated with a matching propensity score procedure. We find that the acquisitions of French firms by foreign companies boost R&D spending. There is a simultaneous rise in the external and in-house R&D expenditures of French acquired firms. R&D is more contracted out to local research providers, in particular to local public laboratories and universities. The increase in internal R&D spending benefits to development, but also basic and applied research. Finally, the growth of the R&D budget is not only financed by internal resources but also receives financing from external partners, especially parent companies. Thus, our results call into question the idea that foreign takeovers hamper the R&D development of target firms and are detrimental to the national innovation system of the host country. First, acquisitions appear to bring efficiency gains enough to counterbalance the various costs of integration and market power effects, pushing firms to invest more in R&D. Acquisitions do not seem to incite managers to take shorter term and more financial driven decisions at the expense of R&D. Second, when motivated by technology sourcing and overseas R&D development, acquisitions might be used to access the specific know-how of target firms and to tap into the knowledge of the national innovation system. Then, purchaser firms could be more likely to develop the innovative capability of target firms and to strengthen their linkages with local partners than to reduce them and relocate R&D abroad.  相似文献   
76.
Parallel computation approaches for flexible multibody dynamics simulations   总被引:1,自引:0,他引:1  
Finite element based formulations for flexible multibody systems are becoming increasingly popular and as the complexity of the configurations to be treated increases, so does the computational cost. It seems natural to investigate the applicability of parallel processing to this type of problems; domain decomposition techniques have been used extensively for this purpose. In this approach, the computational domain is divided into non-overlapping sub-domains, and the continuity of the displacement field across sub-domain boundaries is enforced via the Lagrange multiplier technique. In the finite element literature, this approach is presented as a mathematical algorithm that enables parallel processing. In this paper, the divided system is viewed as a flexible multibody system, and the sub-domains are connected by kinematic constraints. Consequently, all the techniques applicable to the enforcement of constraints in multibody systems become applicable to the present problem. In particular, it is shown that a combination of the localized Lagrange multiplier technique with the augmented Lagrange formulation leads to interesting solution strategies.  相似文献   
77.
Online citizen science allows us to bridge the gap between researchers and nonresearchers and to improve the scientific literacy of nonresearchers. The aims of the present study were (a) to determine whether a 5‐week randomized control trial conducted by teachers in their classroom could improve 7‐ to 12‐year‐old children's inhibitory control (IC) and (b) to provide proof of concept that online scientific research projects can provide meaningful results in the context of education. As expected, children in the IC training group improved their IC efficiency to a greater extent than children in the control training group. We provide the first evidence that such online scientific research projects can be effective in improving children's IC abilities and bridge the gap between the lab and the classroom.  相似文献   
78.
The aim of this study was to determine the effects of Chinese martial arts practice on postural reaction control after perturbation. Participants standing in Romberg tandem posture were subjected to an unexpected lateral platform translation with the eyes open or closed at two translation amplitudes. The peak displacement of the centre of pressure and of the centre of mass, and the onset latency of muscular activity (tibialis anterior, gastrocnemius, lumbodorsal muscular group, and rectus abdominis), were evaluated for martial arts practitioners and for sport and non-sport participants. Compared with the sport and non-sport participants, the martial arts group showed lower maximal centre of pressure and centre of mass peak displacements in both the lateral and anterior - posterior directions, but no difference was found in the onset of muscular responses. We conclude that martial arts practice influences postural reaction control during a fixed-support strategy in a tandem task. The martial arts group used the ankle joint more frequently than the sport and non-sport participants, especially in the eyes-closed conditions. Our results suggest that the better balance recovery in the martial arts group is a consequence of better control of biomechanical properties of the lower limbs (e.g. through muscular response by co-contraction), not a change in the neuromuscular temporal pattern.  相似文献   
79.
A droplet-based micro-total-analysis system involving biosensor performance enhancement by integrated surface-acoustic-wave (SAW) microstreaming is shown. The bioreactor consists of an encapsulated droplet with a biosensor on its periphery, with in situ streaming induced by SAW. This paper highlights the characterization by particle image tracking of the speed distribution inside the droplet. The analyte-biosensor interaction is then evaluated by finite element simulation with different streaming conditions. Calculation of the biosensing enhancement shows an optimum in the biosensor response. These results confirm that the evaluation of the Damköhler and Peclet numbers is of primary importance when designing biosensors enhanced by streaming.It has been pointed out that biosensing performances can be limited by the diffusion of the analytes near the sensing surface.1 In the case of low Peclet number hydrodynamic flows, typical of microfluidic systems, molecule displacements are mainly governed by diffusive effects that affect time scales and sensitivity. To overcome this problem, the enhancement of biosensor performance by electrothermal stirring within microchannels was first reported by Meinhart et al.2 Other authors3, 4 numerically studied the analyte transport as a function of the position of a nanowire-based sensor inside a microchannel, stressing on the fact that the challenge for nanobiosensors is not the sensor itself but the fluidic system that delivers the sample. Addressing this problem, Squires et al.5 developed a simple model applicable to biosensors embedded in microchannels. However, the presented model is limited to the case of a steady flow. The use of surface-acoustic waves (SAWs) for stirring in biomicrofluidic and chemical systems is becoming a popular investigation field,6, 7, 8, 9 especially to overcome problems linked to steady flows by enhancing the liquid∕surface interaction.1, 10, 11 The main challenges that need to be addressed when using SAW-induced stirring are the complexity of the flow and its poor reproducibility. However, some technical solutions were proposed to yield a simplified microstreaming. Yeo et al. presented a centrifugation system based on SAW that produces the rotation of the liquid in a droplet in a reproducible way by playing on the configuration of the transducers and reflectors,12 and presented a comprehensive experimental study of the three-dimensional (3D) flow that causes particle concentration in SAW-stirred droplets,13 revealing the presence of an azimuthal secondary flow in addition to the main vortexlike circular flow present in acoustically stirred droplets. The efficiency of SAW stirring in microdroplets to favorably cope with mass transport issues was finally shown by Galopin et al.,14 but the effect of the stirring on the analyte∕biosensor interaction was not studied. It is expected to overcome mass transport limitations by bringing fresh analytes from the bulk solution to the sensing surface.The studied system, described in Fig. Fig.1,1, consists of a microliter droplet microchamber squeezed between a hydrophobic piezoelectric substrate and a hydrophobic glass cover. Rayleigh SAWs are generated using interdigitated transducers (interdigital spacing of 50 μm) laid on an X-cut LiNbO3 substrate.1, 15, 16 The hydrophobicity of the substrate and the cover are obtained by grafting octadecyltrichlorosilane (OTS) self-assembled monolayers (contact angle of 108° and hysteresis of 9°). To do so, the surface is first hydroxylized using oxygen plasma (150 W, 100 mT, and 30 sccm3 O2) during 1 min and then immersed for 3 h into a 1 mM OTS solution with n-hexane as a solvent.Open in a separate windowFigure 1(a) General view of the considered system. (b) Mean value of the measured speeds within the droplet as a function of the inlet power before amplification.When Rayleigh waves are radiated toward one-half of the microchamber, a vortex is created in the liquid around an axis orthogonal to the substrate due to the momentum transfer between the solid and the liquid. This wave is generated under the Rayleigh angle into the liquid.Speed cartographies of the flow induced in the droplet are realized using the particle image tracking technique for different SAW generation powers. To do so, instantaneous images of the flow are taken with a high-speed video camera at 200 frames∕s and an aperture time of 500 μs on a 0.25 μl droplet containing 1 μm diameter fluorescent particles. Figure Figure11 shows the mean speed measured in the droplet as a function of the inlet power. The great dependence of the induced mean speed with the SAW power enables a large range of flow speeds in the stirred droplet. Moreover, the flow was visualized with a low depth of field objective. It was found to be circular and two dimensional (2D) in a large thickness range of the droplet.The binding of analytes to immobilized ligands on a biosensor is a two step process, including the mass transport of the analyte to the surface, followed by a complexation step,AbulkkmAsurface+Bka,kdAB(1)with km as the constant rate for mass transport from and to the sensor, and ka and kd as the constant rates of association and dissociation of the complex.At the biosensor surface, the reaction kinetics consumes analytes but their transport is limited by diffusive effects. In this case, the Damköhler number brings valuable information by comparing these two effects. Calling the characteristic time of reaction and diffusion, respectively, τC and τM, the mixing time in diffusion regime can be approximated by τMh2D with D as the diffusion coefficient and h a characteristic length of the microchannel. Calling RT the ligand concentration on the surface in mole∕m2, the Damköhler number (Da) can be written asDa=τMτC=kaRThD.(2)Depending on the type of reaction, the calculation of Da helps determine if a specific biointeraction will benefit from a mass SAW-based microstreaming. If the Damköhler number is low, the reaction is slow compared to mass transport and the reaction will not significantly benefit from microstirring. For example, the hybridization of 19 base single stranded DNA in a microfluidic system with a characteristic length of 500 μm is characterized by a Damköhler number of 0.07 and is therefore not significantly influenced by mass transport. On the contrary, the binding of biotin to immobilized streptavidin is characterized by a Da number of approximately 104. In this case, the stirring solution will significantly improve the reaction rate.COMSOL numerical simulations were carried out to study the efficiency of the SAW stirring in the case of a droplet-based microbioreactor with a diameter of 1 mm. Assuming a 2D flow, the simulated model takes into account the convective and diffusive effects in the analyte-carrying fluid and the binding kinetics on the biosensor surface. This approach was thoroughly developed by Meinhart et al.2On the biosensor surface, the following equations are solved:Bt=kacs(RTB)kdB,(3)Bt=D|cy|y=0(4)with c as the local concentration of analytes in the droplet and B as the surface concentration of bound analytes on the biosensor surface. Simulation results show that a depleted zone is formed near the biosensor in the case of an interaction without stirring. This zone is characterized by a low concentration of analytes and results from the trapping of analytes on the biosensor surface, thus creating a concentration gradient on the vicinity of the biosensor. When stirring is applied, the geometry of the depleted zone is modified, as it is pushed in the direction of the flow. The geometry of the depleted zone then depends on many parameters, among which the diffusion coefficient D, the speed distribution of the flow (not only near the biosensor but also in the whole microfluidic system), and the reaction kinetics on the biosensor. In our case, which is assimilated to a simple circular flow, the depleted zone reaches a permanent state consisting of an analyte-poor layer situated in the exterior perimeter of the stirred droplet. The diffusion of analytes is then limited again by diffusion from the inner part of the droplet toward its exterior perimeter (see Fig. Fig.22).Open in a separate windowFigure 2(a) Mean concentration of bound analytes vs time for different mean flow speeds. (b) The obtained concentration profiles with and without circular stirring, t=10 000 s.The initial analyte and receptor concentrations are, respectively, 0.1 nM in the solution and 3.3×10−3 nM m on the biosensor surface, the diffusion coefficient is D=10−11 m2 s−1, and the reaction constants are ka=106 M−1 s−1 and kd=10−3 s−1. Simulations show that the mean concentration of bound analytes highly increases with the flow speed, improving the efficiency of the biosensing device. To evaluate the benefits of in situ microstreaming with SAW, the same simulations were conducted for Da numbers ranging from 104 to 108 M−1∕s, by ranging the diffusion coefficient from 4×10−12 to 4×10−9 m2∕s, and the association coefficient ka from 104 to 108 M−1∕s. The enhancement factor of analyte capture, defined as the ratio of the binding rate with streaming B and the binding rate without streaming B0, is plotted in Fig. Fig.33 for different values of Da. Calculations are done in the case of a mean flow speed of 0.5 mm∕s.Open in a separate windowFigure 3(a) Enhancement factor (defined as the ratio between binding rate with streaming B and binding rate without streaming B0) for different Damkhöler numbers and (b) normalized enhancement factor for different Peclet numbers.One can notice the saturation of the enhancement factor curve for large value of Da to the value of 3.5 for high Da. This can be explained by the fact that for large kaDa ratios, the analytes, which normally require penetration in the depleted zone by diffusion, do not have time to interact with the biosensor when they pass in the vicinity of its surface. The efficiency of the streaming is then reduced for large values of Da. In the case of our specific flow configuration, the enhancement factor reaches 3.2 for the interaction of streptavidin on immobilized biotin (Da=103).The reported simulation results can be compared to an experimental value obtained using the droplet-based surface plasmon resonance sensor streamed in situ using SAW reported by Yeo et al.12 By monitoring the streptavidin∕biotin binding interaction on an activated gold slide, they showed that SAW stirring brings an improvement factor of more than 2. This difference can be accounted to the high complexity of the induced 3D flow, which was modeled in a simple manner in our calculations.Other factors must be taken into account when optimizing the improvement factor, such as the flow velocity and the characteristic length of the mixing. To do so, the Peclet number allows the comparison of the convective and diffusive effects.17 For δC a typical variation in concentration on the distance h, the Peclet number is given byPe=UhD.(5)A significantly high Peclet number causes a decrease in biosensing efficiency as the analytes do not have enough time to interact with the biosensing surface by diffusion through the analyte-poor layer. On the contrary, the case of a low Peclet number corresponds to the diffusion-limited problem. Therefore, for each Damköhler number, there is a Peclet number optimizing this factor. To illustrate this fact, Fig. Fig.3b3b shows the calculation of the enhancement factor as a function of the Peclet number for a given Da.In this paper, we showed that surface loading of typical analytes on a droplet-based biosensor can be highly increased by SAW microstirring. The system permits the enhancement of the biosensing performances by the continuous renewal of the analyte-carrying fluid near the sensing surface. Thanks to mean flow speeds measured up to 1800 μm∕s, the SAW microstreaming can be beneficial to the biosensing of a large range of analyte∕ligand interactions. In addition to the biosensing performance improvement, such a method can be easily integrated in micro-micro-total-analysis systems, which makes it a convenient tool for liquid handling in future biochips.  相似文献   
80.
ABSTRACT

Introduction: Since the 1990s, the notion of intervention has expanded with growing interest in the analysis of practices in Francophone country. French-speaking research community considers intervention sciences as a specific field of research in sport and PE. The aim of this literature review was to characterize the penetration of Francophone research in the English-language literature in physical education and sport concerned with intervention since 2010 in the category ‘Education & Educational Research’ of the Journal Citation Reports (2017). This research was in line with the analysis of the papers presented during six Francophone congresses from 2000 to 2010 of the Association for Research on Intervention in Sport (Musard and Poggi 2015 Musard, Mathilde, and Marie-Paule Poggi. 2015. “Intervention in Physical Education and Sport: Trends and Developments in a Decade of Francophone Research.” Physical Education and Sport Pedagogy 20 (3): 250267. doi:10.1080/17408989.2013.817008.[Taylor & Francis Online], [Web of Science ®] [Google Scholar]).

Methods: The selection of articles was carried out in three stages: selection of journals, selection of articles manually, the second level of selection. The selection of journals is do in this category "Education & Educational Research" (JCR, 2017) focusing primarily on sport and physical education. Six journals met these criteria: Physical Education and Sport Pedagogy, European Physical Education Review, Journal of Teaching in Physical Education, Sport Education and society, Quest, Journal of Hospitality Leisure Sport & Tourism Education. Then, the selection of articles was manually analyzing all the publications of each journal since 2010 (almost 2000 articles) according to inclusion criteria "sport or physical education", "francophone authors", and "intervention". Each 46 articles selected was classified according to its theoretical framework. The last stage of selection corresponded to an analyze and an extension of the literature review by a French-speaking specialist in each theoretical framework.

Results: The results show that French-language research on/in/for intervention is in close connection with the international tradition. Some approaches such as didactique, a technological approach, and course of action, have a Francophone specificity based on various international theoretical anchors; others such as motor learning, social psychology, ecological approach come from non-French-speaking international theoretical frameworks.

Discussion and conclusion: These findings raise the question of the Francophone specificity of intervention sciences. Beyond particular French-speaking theoretical frameworks, concepts and concerns join Anglophone traditions. As in the international fields of ‘sport pedagogy’ or ‘praxis’, the Francophone intervention sciences are composed of a diversity of theoretical approaches and are focused towards an epistemology of action. These two communities can enrich each other and deserve more interaction and exchange.  相似文献   
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