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41.
Jason K. W. Lee 《Journal of sports sciences》2013,31(9):975-985
Abstract Nine males cycled at 53% (s = 2) of their peak oxygen uptake ([Vdot]O2peak) for 90 min (dry bulb temperature: 25.4°C, s = 0.2; relative humidity: 61%, s = 3). One litre of flavoured water at 10 (cold), 37 (warm) or 50°C (hot) was ingested 30 – 40 min into exercise. Immediately after the 90 min of exercise, participants cycled at 95%[Vdot]O2peak to exhaustion to assess exercise capacity. Rectal and mean skin temperatures and heart rate were recorded. The gradient of rise in rectal temperature was influenced (P < 0.01) by drink temperature. Mean skin temperature was highest in the hot trial (cold trial: 34.2°C, s = 0.5; warm trial: 34.4°C, s = 0.5; hot trial: 34.7°C, s = 0.6; P < 0.01). Significant differences were observed in heart rate (cold trial: 132 beats · min?1, s = 13; warm trial: 134 beats · min?1, s = 12; hot trial: 139 beats · min?1, s = 13; P < 0.05). Exercise capacity was similar between trials (cold trial: 234 s, s = 69; warm trial: 214 s, s = 52; hot trial: 203 s, s = 53; P = 0.562). The heat load and debt induced via drinking resulted in appropriate thermoregulatory reflexes during exercise leading to an observed heat content difference of only 33 kJ instead of the predicted 167 kJ between the cold and hot trials. These results suggest that there may be a role for drink temperature in influencing thermoregulation during exercise. 相似文献
42.
Galef BG 《Learning & behavior》2004,32(1):53-61
I review literature on four different approaches to the study of traditions in animals: observation of free-living animals,
laboratory experiment, armchair analysis, and field experiment. Because, by definition, a tradition entails social learning
of some kind, it is difficult, perhaps impossible, to establish that a behavior is in fact traditional without knowledge of
how it develops. Observations of free-living animals often provide strong circumstantial evidence of a tradition. However,
even in the view of several researchers who have studied possibly traditional behaviors in natural populations, observation
alone has not proven sufficient to show that social learning contributes to development of behaviors of interest. The relevance
of laboratory experiments to the understanding of the development of behaviors in free-living animals is always open to challenge.
Armchair analyses of field data can produce interesting hypotheses but cannot test them. Field experiments to determine how
behaviors of interest develop in population members provide a promising way forward. 相似文献
43.
Fu-Ming Chen Jason Sheng-Hong Tsai Ying-Ting Liao Shu-Mei Guo Ming-Chung Ho Fu-Zen Shaw Leang-San Shieh 《Journal of The Franklin Institute》2014
An improvement on the transient response of tracking for the sampled-data system based on an improved PD-type iterative learning control (ILC) is proposed in this paper. The developed analog ILC method and the high-gain property tracker design methodology are first combined to significantly reduce learning epochs and overcome the initial condition shift problem and discontinuous reference input in the traditional ILC. Besides, the proposed ILC improves the transient response and decreases the rate of weighting matrices Q to R under the traditional linear quadratic tracker design. First, the off-line observer/Kalman filter identification (OKID) is used to determine the appropriate (low-) order system parameters and state estimator for the physical system with unknown system equation, so that the model-based PD-type ILC can be implemented for practical applications. Then, to improve the transient response and decrease the control effort, the proportional difference type (PD-type) ILC algorithm is combined with the high-gain property linear quadratic tracker (LQT) design to construct the high performance tracker for the model-based sampled-data systems. Furthermore, the discrete-time version high performance tracker design for the unknown stochastic sampled-data system via the iterative learning control method is proposed in this paper based on the Euler method and the digital redesign approach. Finally, some examples are given for illustrating the effectiveness of the proposed method. 相似文献
44.
Jason Owen-Smith 《Research Policy》2003,32(9):1695-1711
We extend debates about the sources of university capabilities at research commercialization. Drawing upon quantitative data for a panel of 89 research-intensive US universities and interview data from two academic licensing offices, we model the relationship between technology transfer experience, embeddedness in biotechnology industry networks, basic science quality and capacity, and citation impact measures of university life science patents. Technology licensing officers draw upon the expertise of corporate partners to evaluate the potential impact of invention disclosures. The information gleaned through network ties to industry enables well-connected institutions to develop higher impact patent portfolios. Reaping the benefits of such connections, however, requires experience in balancing academic and corporate priorities to avoid the danger of ‘capture’ by industrial interests as overly tight connections limit patent impact. This pattern of diminishing returns to connectivity is robust across multiple citation measures of patent quality. 相似文献
45.
Jason Ravitz 《Peabody Journal of Education》2013,88(3):290-312
This study describes the status of small school reforms in U.S. high schools and contemplates their future. It asks how cultural and instructional reforms differ across school reform types. Analyses focus on indicators of teacher and student culture as well as instructional reforms including project-based learning (PBL) and other inquiry-related practices. Findings are based on data from a national survey completed by 395 high school teachers who were responsible for and had used PBL in core academic subjects. Study participants taught in large, comprehensive high schools; in schools that had converted to small learning communities; and in newly created small school start-ups. Some of these small schools and conversions were based on a reform model, and others were not. Teachers in reform model schools reported the greatest number of cultural and instructional reforms, followed by teachers in other small schools. Reform models were particularly strong on instructional reforms and student culture. In general, start-up teachers reported more success implementing reforms than teachers in conversion schools, and teacher culture was reformed much more often than student culture and instruction. These findings help shed light on how widely practices and conditions have spread throughout the broader small schools movement, and which of these (including extensive PBL use) only seem to flourish in schools that subscribe to a holistic reform model. 相似文献
46.
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48.
Braided composite materials for the production of lightweight, high rigidity golf shafts 总被引:1,自引:1,他引:0
Braiding is not currently used in the production of golf shafts. The objective of this work was to develop, through a modelling
process consisting of altering lamina sequence, a golf shaft, using braided laminas, which would have mass, stiffness and
torque comparable to commercially available composite and steel shafts. A 2D conical braided composite model was previously
developed and validated to predict elastic constants of braided closed meshed structures. Energy methods were used to calculate
the stiffness and torque of shafts using prescribed industry approaches. Shaft mass was calculated based on geometry and density
of constitutent materials. Modelled shafts had both braided and unidirectional layers and compared favourably with or were
better than commercially available composite and steel shafts in terms of deflection force and twist angle; they had the same
weight as composite shafts but were much lighter than steel shafts. If these findings are verified, braided composites would
be a viable and effective approach to the design of future golf shafts. 相似文献
49.
This study employs issue ownership theory to examine the partisan dynamics surrounding the idea of American exceptionalism in presidential discourse. We conducted a content analysis of invocations of American exceptionalism in all major U.S. presidential addresses—domestic and foreign—from the end of World War II through Trump’s 1st year in office. We find that even though Republicans have traditionally claimed ownership of American exceptionalism, patterns in presidential discourse tell a very different story. Specifically, our results show (a) in domestic contexts, Republican and Democratic presidents were very similar in their invocations of American exceptionalism during the Cold War but that Democrats have held a substantial advantage over Republicans throughout the post–Cold War era, including on issue areas that Republicans are perceived to “own” (e.g. national security); (b) in foreign contexts, Democrats have been much more outspoken in their embrace of American exceptionalism throughout both the Cold War and post–Cold War; and (c) President Trump has diverged significantly, both in substance and frequency, from his Democratic and Republican predecessors in his invocation of American exceptionalism. We reflect on the implications of these findings on our broader understanding of issue—and trait—ownership, presidential discourse, and American exceptionalism in American politics. 相似文献
50.
The effect of technology-enhanced learning (TEL) strategies in higher education has arguably been transformative despite the not-insignificant barriers existing in this context. Throughout the discourse very little attention has been paid to those primarily responsible for this implementation—academic teaching staff. This paper aims to highlight the impact of academic workload allocations, an often silent barrier to the uptake of TEL strategies in higher education. We will discuss the effects of academic identity and culture, preferential time allocation to associative activities, academic technological capacity, university policies and workload and funding models on the uptake, and implementation on TEL in higher education. Our aim is to highlight the risks to staff, students and institutions should these concerns not be addressed and to propose a model for utilisation by all staff responsible for implementing flexible workload models supportive of further implementation of TEL strategies across the sector. 相似文献