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   29483篇
  免费   469篇
  国内免费   61篇
教育   20841篇
科学研究   2858篇
各国文化   261篇
体育   2441篇
综合类   108篇
文化理论   301篇
信息传播   3203篇
  2022年   222篇
  2021年   382篇
  2020年   515篇
  2019年   773篇
  2018年   1110篇
  2017年   1106篇
  2016年   1045篇
  2015年   686篇
  2014年   893篇
  2013年   5149篇
  2012年   968篇
  2011年   972篇
  2010年   712篇
  2009年   650篇
  2008年   717篇
  2007年   703篇
  2006年   630篇
  2005年   1145篇
  2004年   900篇
  2003年   733篇
  2002年   560篇
  2001年   603篇
  2000年   475篇
  1999年   413篇
  1998年   234篇
  1997年   234篇
  1996年   278篇
  1995年   258篇
  1994年   202篇
  1993年   212篇
  1992年   334篇
  1991年   308篇
  1990年   311篇
  1989年   308篇
  1988年   258篇
  1987年   308篇
  1986年   269篇
  1985年   308篇
  1984年   249篇
  1983年   215篇
  1982年   197篇
  1981年   167篇
  1980年   157篇
  1979年   260篇
  1978年   182篇
  1977年   172篇
  1976年   155篇
  1975年   142篇
  1974年   152篇
  1971年   142篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
We have studied the efficiency of research in the EU by a percentile-based citation approach that analyzes the distribution of country papers among the world papers. Going up in the citation scale, the frequency of papers from efficient countries increases while the frequency from inefficient countries decreases. In the percentile-based approach, this trend, which is uniform at any citation level, is measured by the ep index that equals the Ptop 1%/Ptop 10% ratio. By using the ep index we demonstrate that EU research on fast-evolving technological topics is less efficient than the world average and that the EU is far from being able to compete with the most advanced countries. The ep index also shows that the USA is well ahead of the EU in both fast- and slow-evolving technologies, which suggests that the advantage of the USA over the EU in innovation is due to low research efficiency in the EU. In accord with some previous studies, our results show that the European Commission’s ongoing claims about the excellence of EU research are based on a wrong diagnosis. The EU must focus its research policy on the improvement of its inefficient research. Otherwise, the future of Europeans is at risk.  相似文献   
152.
This study examines the relationship between course intensity and long-term retention on graduate level counseling students enrolled in a research and statistics course. It confirms earlier findings of time and learning studies, which have primarily dealt with end-of-course outcomes, that there is no effect due to scheduling format. In this study, older students performed significantly higher on a six-month follow-up test than younger students. Students who had previous, related course work scored significantly higher in final course grades than students with no prior course work, however, differences were moderated and no longer significant at the time of follow-up. Implications from these findings are discussed.Rebecca LaFountain is an assistant professor in the Department of Counseling, Shippenburg University of Pennsylvania. She earned an Ed.D in Counseling from the College of William and Mary, an M.S. in Counseling from Iowa State University, and a B.A. in French from Grand Valley State University. She is a Licensed Psychologist and a Certified Clinical Mental Health Counselor. Her primary professional interests include the teaching of research and statistics so that it is not threatening; Adlerian psychology; and, Solution-Focused counseling.  相似文献   
153.
154.
ABSTRACT

Participation in youth sport is positively associated with physical fitness and performance. The purpose of the current study was to examine if physical fitness measures during childhood and early adolescence predicted high school sport participation. Participants included youth in the Michigan State University Motor Performance Study. Measures consisted of the endurance shuttle run, Wells sit-and-reach, jump and reach, standing long jump, agility shuttle run and 30-yard dash. Individual, generalized estimating equation models were used to estimate the association between each measure and the odds of participating in high school sport. For both sexes, the endurance shuttle run and agility shuttle run were related to sport participation. For boys only, the long jump and 30-yard dash were also associated with sport participation. Better physical fitness and performance across several dimensions in childhood, including those related to motor skills, enhanced the likelihood of sport participation in high school.  相似文献   
155.
156.
157.
With the rise of microfluidics for the past decade, there has come an ever more pressing need for a low-cost and rapid prototyping technology, especially for research and education purposes. In this article, we report a rapid prototyping process of chromed masks for various microfluidic applications. The process takes place out of a clean room, uses a commercially available video-projector, and can be completed in less than half an hour. We quantify the ranges of fields of view and of resolutions accessible through this video-projection system and report the fabrication of critical microfluidic components (junctions, straight channels, and curved channels). To exemplify the process, three common devices are produced using this method: a droplet generation device, a gradient generation device, and a neuro-engineering oriented device. The neuro-engineering oriented device is a compartmentalized microfluidic chip, and therefore, required the production and the precise alignment of two different masks.  相似文献   
158.
159.
赋权少数族裔学生:一个干预框架   总被引:1,自引:0,他引:1  
吉姆康明斯提出了一个理论框架来分析少数族裔学生学业失败的原因,以及之前曾尝试过的,诸如补偿教育和双语教育这样的教育改革相对缺乏成功的原因。这些尝试之所以没有成功是因为教育者和少数族裔学生之间的关系以及学校和少数族裔社区的关系都没有得到显著的改变。研究旨在为教育者提供一些改变这些关系,从而赋权学生,使得学生在学业上取得成功的方法。  相似文献   
160.
ABSTRACT

The aim of the present study was to investigate the existence of a relative age effect (RAE) on physical fitness of preschoolers. Anthropometry and physical fitness were assessed in 3147 children (3–5 years old) using the PREFIT battery. Based on the birth year, participants were divided into 3year groups (3-, 4- and 5-years). Within each year group, 4quarter groups were created: quarter 1, preschoolers born from January to March; quarter 2, from April to June; quarter 3, from July to September; quarter 4, from October to December. The MANCOVA analysis revealed a main effect of year group (Wilks’ λ = 0.383; F10,5996 = 369.64; p < 0.001, ηp 2 = 0.381) and of quarter (Wilks’ λ = 0.874; F15,8276.6 = 27.67; p < 0.001; ηp 2 = 0.044) over the whole battery of tests. To the best of our knowledge, this is the first study to report the existence of RAE at the preschool stage. In general, performance improved as the relative age increased (i.e., those born in quarter 1 performed better than those in the other quarters). Individualization strategies should be addressed within the same academic year not only in elementary or secondary years but also in preschoolers.  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