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21.
Skiing manufacturers depend on the development of new skis on trial and error cycles and extensive product testing. Simulation
tools, such as the finite element method, might be able to reduce the number of required testing cycles. However, computer
programs simulating a ski in the situation of a turn so far lack realistic ski–snow interaction models. The aim of this study
was to (a) implement a finite element simulation of a ski in a carved turn with an experimentally validated ski–snow interaction
model, and (b) comparison of the simulation results with instantaneous turn radii determined for an actual carved turn. A
quasi-static approach was chosen in which the ski–snow interaction was implemented as a boundary condition on the running
surface of the ski. A stepwise linear function was used to characterise the snow pressure resisting the penetration of the
ski. In a carved turn the rear section of the ski interacts with the groove that forms in the snow. Two effects were incorporated
in the simulation to model this situation: (a) the plasticity of the snow deformation, (b) the influence of the ski’s side-cut
on the formation and shape of this groove. The simulation results agreed well with experiments characterising snow penetration.
Implementation of the groove in the ski–snow interaction model allowed calculation of the instantaneous turn radii measured
in actual turns, but also caused significant numerical instability. The simulation contributes to the understanding of the
mechanical aspects of the ski–snow interaction in carved turns and can be used to evaluate new ski designs. 相似文献
22.
Knowledge Management Research & Practice - Being competitive entails continuously performing product and process innovations. The acquisition of externally generated R&D is therefore... 相似文献
23.
Wolfgang Sieghart Markus Peck-Radosavljevic 《Wiener klinische Wochenschrift Education》2009,4(1):33-41
Ohne Zusammenfassung 相似文献
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Joachim Grabowski Christian Weinzierl Markus Schmitt 《Journal of Research in Reading》2010,33(1):39-53
Particularly in primary school, good performance on copy tasks is an important working technique. With respect to writing skills, copying is a very basic process on which more complex writing abilities are based. We studied the copying ability of second and fourth graders across four types of symbols which vary with respect to their semantic and phonological characteristics: arbitrary graphical objects, unpronounceable consonant strings, numerals and meaningful text. Results show, in terms of average copying speed, significant effects of both factors: fourth graders performed generally faster than second graders, and for both class levels, the number of copied characters per time decreased from meaningful text to graphical objects, all pair-wise contrasts between symbol types being statistically significant. Moreover, a significant interaction shows that fourth graders improved more when copying symbols that form pronounceable chunks, namely meaningful text and numerical strings. This indicates an increasing role of phonological (and probably also semantic) processes involved in copying across primary school. 相似文献
26.
The purpose of this pilot study was to investigate the effect of playing-position-dependent training routines in soccer on the various muscle–tendon parameters. We hypothesized that there would be differences in such parameters between competitive goalkeepers and midfielders. According to their playing position, 21 healthy volunteers were assigned to goalkeeper (n?=?7), midfielder (n?=?7), and control (n?=?7) groups. To investigate the muscle–tendon parameters, we determined the maximum dorsiflexion range of motion and the corresponding muscle thickness, fascicle length, and pennation angle of the gastrocnemius medialis. Passive resistive torque and maximum voluntary contraction were measured with a dynamometer. Observation of muscle–tendon junction displacement with ultrasound allowed us to determine length changes in the tendon and muscle, respectively, and hence to calculate stiffness. There was no significant difference in range of motion, passive resistive torque, muscle–tendon stiffness, and the examined structural parameters (e.g., tendon stiffness) between the three groups. However, we found a significant difference in maximum voluntary contraction torque between the goalkeepers and midfielders vs. the controls, but not between the athlete groups. Habitual training leads to higher muscle strength in soccer players compared to less active persons. However, soccer training does not lead to specific muscle and tendon architecture adaptations according to playing position or when compared to less active persons. 相似文献
27.
Angela Gebert Markus Gerber Uwe Pühse Philippe Gassmann Hanspeter Stamm Markus Lamprecht 《European Journal of Sport Science》2018,18(8):1168-1176
The objective of this study is to analyse context, causes, and characteristics of injuries in non-professional soccer. Therefore, a retrospective telephone survey was carried out with persons who were injured while playing soccer and who reported this accident to the Swiss National Accident Insurance Fund (Suva). Based on these data, an analysis of 708 soccer injuries was performed. The findings show that 30.1% of the injuries occurred during informal soccer play, and 75.4% of the injured persons were soccer club members. 53.0% of all injuries were caused by contact and 29.5% by foul play. Foul play was not associated with injury severity. With respect to injury severity, twisting/turning and being tackled by an opponent were identified as the most influental injury causes. Moreover, the risk of being severely injured was particularly high players of the 30+/40+ amateur leagues. In conclusion, the findings highlight that 30+/40+ league players are a major target group for the prevention of severe soccer injuries. Soccer clubs may constitute an appropriate multiplier for implementing prevention strategies such as fair play education, healthy play behaviours, and prevention programmes. Finally, a better understanding of injury situations leading to severe injuries is needed to improve injury prevention. 相似文献
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Christiane Gebhardt Markus C. Pohlmann 《The Journal of High Technology Management Research》2013,24(2):153-160
During the last twenty years the German programme family Entrepreneurial Regions has formed a landscape of strategy driven clusters, characterized by networking relationships along the value chain between SME, university and research laboratories. Initiated by the Federal Government the Entrepreneurial Regions Programme (ERP) was directed at rebooting East Germany's innovative strength and reviving the declined industrial basis as well as integrating the small technology oriented firms, remnants from GDR research labs into the global economy. The study carried out in 2010 and 2011 was based on a multi-method approach and went beyond traditional quantitative indicators such as turnover, job growth and number of patents, by focusing on interrelated qualitative and early indicators in a systemic approach. Apart from the continuity of Financial Investments, General Management Competences, Networking competences as well as Entrepreneurial Thinking and Acting were identified to be relevant key drivers for many other interconnected indicators of cluster development. We discuss the integration of Management Science into the context of regional innovation, organizational studies and industrial strategy and will shed light on the policy implications for the assessment and monitoring of clusters as well as on the management requirements of clusters. An outcome of our study is an indicator system that enriches the conventional indicator set for the evaluation of robustness and viability of politically initiated clusters. 相似文献
30.
Markus J. Klusemann David B. Pyne Carl Foster Eric J. Drinkwater 《Journal of sports sciences》2013,31(14):1463-1471
Abstract Differences in physiological, physical, and technical demands of small-sided basketball games related to the number of players, court size, and work-to-rest ratios are not well characterised. A controlled trial was conducted to compare the influence of number of players (2v2/4v4), court size (half/full court) and work-to-rest ratios (4x2.5 min/2x5 min) on the demands of small-sided games. Sixteen elite male and female junior players (aged 15–19 years) completed eight variations of a small-sided game in randomised order over a six-week period. Heart rate responses and rating of perceived exertion (RPE) were measured to assess the physiological load. Movement patterns and technical elements were assessed by video analysis. There were ~60% more technical elements in 2v2 and ~20% more in half court games. Heart rate (86 ± 4% & 83 ± 5% of maximum; mean ± SD) and RPE (8 ± 2 & 6 ± 2; scale 1–10) were moderately higher in 2v2 than 4v4 small-sided games, respectively. The 2v2 format elicited substantially more sprints (36 ±12%; mean ±90% confidence limits) and high intensity shuffling (75 ±17%) than 4v4. Full court games required substantially more jogging (9 ±6%) compared to half court games. Fewer players in small-sided basketball games substantially increases the technical, physiological and physical demands. 相似文献