首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   138篇
  免费   2篇
教育   79篇
科学研究   9篇
各国文化   2篇
体育   29篇
文化理论   1篇
信息传播   20篇
  2023年   2篇
  2022年   2篇
  2021年   1篇
  2019年   10篇
  2018年   11篇
  2017年   13篇
  2016年   14篇
  2015年   5篇
  2014年   9篇
  2013年   33篇
  2012年   7篇
  2011年   7篇
  2010年   2篇
  2009年   6篇
  2008年   6篇
  2007年   3篇
  2005年   1篇
  2003年   1篇
  2002年   1篇
  1999年   1篇
  1997年   1篇
  1995年   1篇
  1991年   1篇
  1989年   1篇
  1983年   1篇
排序方式: 共有140条查询结果,搜索用时 46 毫秒
1.
2.
The aim of this study was to identify the dynamics of tactical behaviour emerging on different timescales in football small-sided games and to quantify short- and long-term exploratory behaviour according to the number of opponents. Two teams of four professional male footballers played small-sided games against two different teams with a variable number of opponents (3, 5 and 7). Data were collected using a combination of systematic observation and a non-differential global positioning system (15 Hz). The temporal diversity and structural flexibility of the players were determined by calculating the dynamic overlap order parameter q, entropy and trapping strength. Analysis of the exploratory dynamics revealed two different timescales, forming a different metastable landscape of action for each constraint. Fast dynamics lasted on average a few seconds and consisted of changes in tactical patterns. The long timescale corresponded to the shared tasks of offence and defence lasting tens of seconds. The players’ tactical diversity decreased with an increasing number of opponents, especially in defence. Manipulating numerical imbalance is likely to promote changes in the diversity, unpredictability and flexibility of tactical solutions. The fact that the temporally nested structure of constraints shaped the emergence of tactical behaviour provides a new rationale for practice task design. The manipulation of numerical imbalance on the timescale of a few tens of seconds, on which the exploratory behaviour of players saturates, may help coaches to optimise the exploratory efficiency of the small-sided games.  相似文献   
3.
4.
Ball screens are one of the most frequently used tactical behaviour in elite basketball games. The aim of the present study was to identify their predictors of success related to time, space, players, and tasks performed. The sample was composed of 818 ball screens corresponding to 20 close games (mean differences in score of 3.1 ± 0.8 points) randomly selected from the playoff games of the Spanish Basketball League (2008–2011). Classification tree analysis (CHAID) was used to analyse which variable or combination of variables, better predicts effectiveness during ball screens. The main results allowed identifying interactions with dribbler actions after the screen and the orientation of the screen on the ball. The results showed no interaction with game quarter and quarter minute temporal-related variables in both analyses. The present findings allow improving coaches’ strategic plans that involve selecting the most appropriate offensive approach when performing ball screens.  相似文献   
5.
6.
In this paper strict, non-smooth Lyapunov functions for some non-homogeneous versions of the super-twisting algorithm are proposed. Convergence under the action of bounded perturbations for two basic forms of non-homogeneous algorithms will be studied by means of the Lyapunov functions. Since the homogeneity property cannot be used directly to prove stability of the algorithms, the availability of a Lyapunov function is of great importance for analysis and design in these cases. Moreover, exponential or finite-time and local or global stability are required to be established, since they are not derived from the homogeneity.  相似文献   
7.
The problem of constructing functional observers for linear systems with unknown inputs is considered. Necessary and sufficient conditions for the existence of a proper observer (without differentiations) are revisited. A simple and explicit form of a functional observer is presented. It is shown that when such observer is not proper, it is still possible to use the High-Order Sliding Mode differentiator to implement it. Nevertheless, in such case, additional conditions on the system and the unknown input are required.  相似文献   
8.
A supply chain consists of different processes and when conducting supply chain re-design is necessary to identify the relevant processes and select a target for re-design. Through a literature review a solution is presented here to identify first the relevant processes using the Supply Chain Operations Reference (SCOR) model, then to use Analytical Hierarchy Process (AHP) analysis for target process selection. AHP can aid in deciding which supply chain processes are better candidates to re-design in light of predefined criteria.  相似文献   
9.
10.
The aim of this study was to assess the effects of quality of opposition and match status on technical and tactical volleyball performances, as measured by block, attack, serve, and set actions related to the tasks, space, players, and efficacy of selected game actions. Twenty-five matches from the men's World Cup 2007 were notated and through cluster analysis were classified as "high" (HIGH), "intermediate" (INT) or "low" (LOW) quality. The difference between points scored and points allowed was used to define match status. Multinomial logistic regression identified an association of match status with: set direction (likelihood ratio test [LRT]?=?15.5, P?=?0.017) and block typology (LRT?=?9.6, P?=?0.047) in HIGH vs. HIGH matches; attack player (LRT?=?17.4, P?=?0.026) and block typology (LRT?=?9.2, P?=?0.010) in LOW vs. LOW matches; and serve type (LRT?=?17.4, P?=?0.002), block strategy (LRT?=?53.7, P?<0.001), and serve efficacy (LRT?=?26.0, P?=?0.001) in HIGH vs. LOW matches. Results suggest that volleyball teams took more risky decisions in unbalanced situations. They also carried less risk through technical and tactical decisions in balanced and moderate situations whether they had the advantage or not. Therefore, strategic behaviour was affected by the interaction of quality of opposition and match status, providing a better understanding of volleyball game performance and new insights for practice, competition, and research.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号