全文获取类型
收费全文 | 125714篇 |
免费 | 1913篇 |
国内免费 | 238篇 |
专业分类
教育 | 87647篇 |
科学研究 | 13623篇 |
各国文化 | 2051篇 |
体育 | 9616篇 |
综合类 | 173篇 |
文化理论 | 1146篇 |
信息传播 | 13609篇 |
出版年
2021年 | 960篇 |
2020年 | 1729篇 |
2019年 | 2660篇 |
2018年 | 3182篇 |
2017年 | 3483篇 |
2016年 | 3514篇 |
2015年 | 2407篇 |
2014年 | 3287篇 |
2013年 | 28024篇 |
2012年 | 2453篇 |
2011年 | 2804篇 |
2010年 | 2418篇 |
2009年 | 2693篇 |
2008年 | 2488篇 |
2007年 | 2184篇 |
2006年 | 2440篇 |
2005年 | 2402篇 |
2004年 | 3065篇 |
2003年 | 2429篇 |
2002年 | 2209篇 |
2001年 | 2077篇 |
2000年 | 1736篇 |
1999年 | 1594篇 |
1998年 | 1505篇 |
1997年 | 1562篇 |
1996年 | 1752篇 |
1995年 | 1530篇 |
1994年 | 1515篇 |
1993年 | 1511篇 |
1992年 | 1529篇 |
1991年 | 1444篇 |
1990年 | 1434篇 |
1989年 | 1357篇 |
1988年 | 1206篇 |
1987年 | 1135篇 |
1986年 | 1163篇 |
1985年 | 1427篇 |
1984年 | 1299篇 |
1983年 | 1304篇 |
1982年 | 1276篇 |
1981年 | 1193篇 |
1980年 | 1189篇 |
1979年 | 1238篇 |
1978年 | 1216篇 |
1977年 | 1120篇 |
1976年 | 1022篇 |
1975年 | 817篇 |
1974年 | 809篇 |
1973年 | 778篇 |
1971年 | 639篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
962.
963.
964.
ABSTRACTRecently, 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
965.
Alan M. Nevill Yassine Negra Tony D. Myers Senda Sammoud Helmi Chaabene 《Journal of sports sciences》2020,38(7):787-794
ABSTRACTThis 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
966.
967.
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
968.
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
969.
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
970.