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   118435篇
  免费   1846篇
  国内免费   235篇
教育   82070篇
科学研究   13233篇
各国文化   1978篇
体育   9115篇
综合类   170篇
文化理论   1051篇
信息传播   12899篇
  2022年   497篇
  2021年   922篇
  2020年   1634篇
  2019年   2543篇
  2018年   2997篇
  2017年   3276篇
  2016年   3346篇
  2015年   2294篇
  2014年   3169篇
  2013年   27194篇
  2012年   2300篇
  2011年   2612篇
  2010年   2264篇
  2009年   2576篇
  2008年   2299篇
  2007年   2014篇
  2006年   2299篇
  2005年   2284篇
  2004年   2963篇
  2003年   2286篇
  2002年   2102篇
  2001年   1942篇
  2000年   1604篇
  1999年   1492篇
  1998年   1446篇
  1997年   1505篇
  1996年   1681篇
  1995年   1462篇
  1994年   1457篇
  1993年   1461篇
  1992年   1455篇
  1991年   1374篇
  1990年   1367篇
  1989年   1273篇
  1988年   1152篇
  1987年   1077篇
  1986年   1095篇
  1985年   1368篇
  1984年   1252篇
  1983年   1244篇
  1982年   1224篇
  1981年   990篇
  1980年   950篇
  1979年   1028篇
  1978年   1023篇
  1977年   947篇
  1976年   843篇
  1975年   687篇
  1974年   684篇
  1973年   655篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
ABSTRACT

Recently, there has been much controversy over the International Association of Athletics Federation (IAAF) regulations regarding eligibility to compete and natural testosterone levels in female athletes. Much interest lies in the analysis of Caster Semenya's extraordinary performance. The objective of this work were, a) Complete an analysis of Caster Semenya's results during the 800m finals and b) search for existing similar performances by other female athletes. We analysed the results of the finals of all IAAF World Championships and Olympic Games from 1984–2016, including the 800m results of the Diamond Leagues 2016–2018. Exponential curves were fit to the data to characterise and predict performance for each event. Caster Semenya's finishing times before her ineligibility to compete and after the suspension of the IAAF hyperandrogenism regulation were found to be 1.24% and 1.49%, respectively, faster than the characteristic performance of the elite-standard in the women’s 800m final. Other female athletes, with finishing times faster than the ones predicted by the characteristic curves were also discovered. The percentage difference in performance between Caster Semenya and the other participants did not reach 3% in the 800m event. No conclusions can be drawn regarding extraordinary results ever performed during the 100m, 200m or 400m finals.  相似文献   
962.
ABSTRACT

This study identified key somatic and demographic characteristics that benefit all swimmers and, at the same time, identified further characteristics that benefit only specific swimming strokes. Three hundred sixty-three competitive-level swimmers (male [n = 202]; female [n = 161]) participated in the study. We adopted a multiplicative, allometric regression model to identify the key characteristics associated with 100 m swimming speeds (controlling for age). The model was refined using backward elimination. Characteristics that benefited some but not all strokes were identified by introducing stroke-by-predictor variable interactions. The regression analysis revealed 7 “common” characteristics that benefited all swimmers suggesting that all swimmers benefit from having less body fat, broad shoulders and hips, a greater arm span (but shorter lower arms) and greater forearm girths with smaller relaxed arm girths. The 4 stroke-specific characteristics reveal that backstroke swimmers benefit from longer backs, a finding that can be likened to boats with longer hulls also travel faster through the water. Other stroke-by-predictor variable interactions (taken together) identified that butterfly swimmers are characterized by greater muscularity in the lower legs. These results highlight the importance of considering somatic and demographic characteristics of young swimmers for talent identification purposes (i.e., to ensure that swimmers realize their most appropriate strokes).  相似文献   
963.
964.
Informed by the latest research on how people learn, effective teachers address both aspects of the teaching–learning equation—they engage students in the course material by implementing best teaching practices and they prepare students for learning by sharing best learning practices. The purpose of this study was to evaluate the impact of student‐centered learning practices on students’ perceptions of their ability to learn, specifically in a large enrollment, introductory food science and human nutrition course. Featured student‐centered learning practices included required assignments, optional study tools, and supplemental learning resources. A mixed method survey instrument with 5‐point Likert scales and qualitative, open‐ended questions was used to determine students’ (1) use of optional study tools and supplemental learning resources; (2) perceptions as to the quality and impact of required assignments, optional study tools, and supplemental learning resources to enhance their ability to learn; (3) perceptions as to the usefulness of required assignments, optional study tools, and supplemental learning resources to help them perform better in this course; and (4) overall satisfaction, as a learner, in this course. Overall, students identified study guides (developed using Bloom's taxonomy action verbs) (Mean = 4.34), microthemes (Mean = 4.27), and quizzes (Mean = 4.11) as the most beneficial resources to enhance their learning of the course material. Overall, 85% of students said they were extremely or very satisfied as learners in the course and nearly 75% of the students said the student‐centered learning practices should be offered to future FSHN 101 students.  相似文献   
965.
Educational Psychology Review - In his 1973 article The Structure of ill structured problems, Herbert Simon proposed that solving ill-structured problems could be modeled within the same...  相似文献   
966.
967.
Data from surveys of parents of students in Russian schools of various types in the years 2006 to 2011 show a high level of desire to invest in their children's education. There has been a high degree of stability in aspirations and investment in spite of the economic problems caused by global recession.  相似文献   
968.
969.
970.
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