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   40655篇
  免费   718篇
  国内免费   44篇
教育   29066篇
科学研究   3646篇
各国文化   417篇
体育   3205篇
综合类   46篇
文化理论   344篇
信息传播   4693篇
  2022年   249篇
  2021年   442篇
  2020年   683篇
  2019年   1014篇
  2018年   1402篇
  2017年   1438篇
  2016年   1308篇
  2015年   774篇
  2014年   1138篇
  2013年   8043篇
  2012年   1097篇
  2011年   1173篇
  2010年   868篇
  2009年   863篇
  2008年   979篇
  2007年   877篇
  2006年   788篇
  2005年   735篇
  2004年   689篇
  2003年   622篇
  2002年   674篇
  2001年   801篇
  2000年   707篇
  1999年   689篇
  1998年   377篇
  1997年   408篇
  1996年   458篇
  1995年   410篇
  1994年   369篇
  1993年   341篇
  1992年   535篇
  1991年   501篇
  1990年   543篇
  1989年   512篇
  1988年   468篇
  1987年   458篇
  1986年   432篇
  1985年   534篇
  1984年   420篇
  1983年   387篇
  1982年   322篇
  1981年   305篇
  1980年   268篇
  1979年   416篇
  1978年   322篇
  1977年   294篇
  1976年   261篇
  1975年   232篇
  1974年   229篇
  1973年   227篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
55.
The project of studying children in order to understand them, which lies at the heart of contemporary thinking about children and their education, is misconceived. It rests, jrst of all, upon a false belief that we can only come to know something properly by deliberately and systematically pursuing knowledge of it. Secondly, it offers a paradigm of knowing children which justifies parents and teachers in not giving themselves to children. By re-interpreting the problems that adults experience with children as technical, as arising from lack of information about them, it ignores the personal and moral dimension of adults' relations with children and thus further alienates them from one another.  相似文献   
56.
57.
A completely general three-dimensional dynamic model is presented for the motion of basketball shots that may contact the rim, the backboard, the bridge between the rim and board, and possibly the board and the bridge simultaneously. Non-linear ordinary differential equations with six degrees of freedom describe the ball angular velocity and ball centre position. The model includes radial ball compliance and damping and contains five sub-models: purely gravitational flight, and ball-rim, ball-bridge, ball-board, and ball-bridge-board contact. Each contact sub-model has both slipping and non-slipping motions. Switching between the sub-models depends on the reaction force at, and velocity of, the contact point. Although the model can be used to study shots from any point on the court, we here use it to study the sets of free throw release angle, velocity, angular velocity, and lateral deviation angle that result in success (capture), as well as underhand free throws and those using an under-inflated ball. Free throw shots with larger backspin, lower inflation pressures, and underhand release conditions are shown to result in larger capture percentages.  相似文献   
58.
Longitudinal changes in height, weight and physical performance were studied in 33 Flemish male youth soccer players from the Ghent Youth Soccer Project. The players' ages at the start of the study ranged from 10.4 to 13.7 years, with a mean age of 12.2 +/- 0.7 years. Longitudinal changes were studied over a 5 year period. Peak height velocity and peak weight velocity were determined using non-smoothed polynomials. The estimations of peak height velocity, peak weight velocity and age at peak height velocity were 9.7 +/- 1.5 cm x year-1, 8.4 +/- 3.0 kg x year-1 and 13.8 +/- 0.8 years, respectively. Peak weight velocity occurred, on average, at the same age as peak height velocity. Balance, speed of limb movement, trunk strength, upper-body muscular endurance, explosive strength, running speed and agility, cardiorespiratory endurance and anaerobic capacity showed peak development at peak height velocity. A plateau in the velocity curves was observed after peak height velocity for upper-body muscular endurance, explosive strength and running speed. Flexibility exhibited peak development during the tear after peak height velocity. Trainers and coaches should be aware of the individual characteristics of the adolescent growth spurt and the training load should also be individualized at this time.  相似文献   
59.
This article discusses the changing relationships of authors and publishers, the current trends and challenges they face, and the direction of these relationships in the future. As the STM publishing industry finds itself in the midst of significant technological and economic changes, this article provides background to these changes and looks at the key elements, including open access business development, institutional repository trends, and emerging public financing policies in the future.  相似文献   
60.
Females and youth are frequently described as "special" populations in football literature, but together these two populations outnumber male players. What makes females "special" is that they tend to eat less when training and competing than their male counterparts, leading to lower intakes of energy, carbohydrate, and some nutrients. Youth football players are special in regard to energy and nutrient requirements to promote growth and development, as well as to fuel sport. There is limited research on the dietary habits of these two populations, but the available literature suggests that many female and youth players need to increase carbohydrate intake, increase fluid intake, and develop dietary habits to sustain the demands of training and competition.  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