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   123335篇
  免费   1866篇
  国内免费   254篇
教育   85805篇
科学研究   13485篇
各国文化   1972篇
体育   9505篇
综合类   174篇
文化理论   1064篇
信息传播   13450篇
  2021年   947篇
  2020年   1644篇
  2019年   2557篇
  2018年   3072篇
  2017年   3335篇
  2016年   3388篇
  2015年   2311篇
  2014年   3175篇
  2013年   27209篇
  2012年   2379篇
  2011年   2763篇
  2010年   2332篇
  2009年   2617篇
  2008年   2395篇
  2007年   2107篇
  2006年   2337篇
  2005年   2329篇
  2004年   3014篇
  2003年   2341篇
  2002年   2150篇
  2001年   2082篇
  2000年   1768篇
  1999年   1609篇
  1998年   1461篇
  1997年   1511篇
  1996年   1695篇
  1995年   1462篇
  1994年   1464篇
  1993年   1467篇
  1992年   1537篇
  1991年   1452篇
  1990年   1448篇
  1989年   1378篇
  1988年   1248篇
  1987年   1147篇
  1986年   1186篇
  1985年   1439篇
  1984年   1298篇
  1983年   1312篇
  1982年   1271篇
  1981年   1180篇
  1980年   1166篇
  1979年   1272篇
  1978年   1229篇
  1977年   1129篇
  1976年   1016篇
  1975年   817篇
  1974年   823篇
  1973年   793篇
  1971年   638篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
911.
ABSTRACT

Introduction: Low energy availability (LEA) results in physiological adaptations, which can contribute to unfavourable health outcomes. Little information exists on risk of LEA in active individuals competing in different sports or levels of competition. The aims of this study were to (1) identify risk of LEA in females competing at different levels of competition and (2) investigate associations between risk of LEA, illness and dietary habits. Methods: The validated questionnaire, ‘Low Energy Availability in Females Questionnaire’ was distributed online (November 2016–February 2017) to assess risk of LEA. Twenty-nine additional questions collected information on demographics, illness history and dietary habits. Participants were considered at risk of LEA if they attained a score of?≥?8 and were grouped into: (i) international; (ii) provincial/inter-county; (iii) competitive; and (iv) recreationally active. Chi-square and logistic regression analyses were used to explore differences between those at risk or not at risk of LEA. Results: Risk of LEA was identified in 40% (n?=?331) of 833 participants and was 1.7 and 1.8 times more likely in international and provincial/inter-county athletes compared to those who were recreationally active (International: odds ratios (OR) 1.68, 95% confidence intervals (95%CI) 1.12–2.54; Provincial/inter-county: OR 1.83, 95%CI 1.20–2.77). In participants at risk of LEA, missing >22 days of training during the previous year due to illness occurred 3 times more frequently (OR 3.01, 95%CI 1.81–5.02). Conclusion: Risk of LEA was widespread in this heterogeneous sample. Awareness of LEA and the development of appropriate energy management strategies to ensure athlete health across levels of competition are required.  相似文献   
912.
Virtual and Augmented Realities are advancing technologies that are becoming more popular in gaming and programming communities. However, virtual reality has been in development for decades. As libraries are often at the forefront of offering new and advancing technologies to their communities, virtual and augmented reality programs have become new additions to library services. While gaming is the prominent use of these technologies, virtual and augmented reality affords many educational opportunities. Mississippi State University Libraries have recently added a virtual/augmented reality lab as part of its library program.  相似文献   
913.
914.
In this article, the author attempts to oppose the traditional school pedagogy, which he labels conceptual, with non-classical padagogy of metaphors. According to the author, this type of pedagogy is a better fit for the human mind.  相似文献   
915.
916.
In the article we solve path planning task for an agent being multirotor unmanned aerial vehicle (multicopter). We propose an approach of estimating path geometry constraints based on UAV flight dynamics model and control constraints. Than we introduce a new path finding method which takes into consideration those geometry constraints and study this method both theoretically and empirically.  相似文献   
917.
918.
ABSTRACT

This article answers the question “Are the sourcing practices in Finnish online journalism trustworthy?” Here, trustworthiness is operationalized as the fulfillment of audience expectations towards sourcing practices. To this end, expectations of young Finnish adults (aged 18–28) were compared to the observed practices of Finnish online journalists. A total of 36 news items (from 12 journalists working in three newsrooms, published in 2013 and 2017) were analyzed. The analysis indicates that online journalists’ sourcing practices largely do not conform to this audience segment's expectations. Namely, the audience expects more comprehensive investigation and thorough verification than what is common practice in online journalism. The use of high-credibility sources is both expected and commonplace. The results imply that transparency may be harmful rather than beneficial to journalism's credibility, as the unveiled practices do not always meet audience expectations.  相似文献   
919.
920.
Until recently, little attention has been paid in the school classroom to creationism and almost none to intelligent design. However, creationism and possibly intelligent design appear to be on the increase and there are indications that there are more countries in which schools are becoming battle‐grounds over them. I begin by examining whether creationism and intelligent design are controversial issues, drawing on Robert Dearden's epistemic criterion of the controversial and more recent responses to and defences of this. I then examine whether the notion of ‘worldviews’ in the context of creationism is a useful one by considering the film March of the Penguins. I conclude that the ‘worldviews’ perspective on creationism is useful for two reasons: first it indicates the difficulty of using the criterion of reason to decide whether an issue is controversial or not; secondly, it suggests that standard ways of addressing the diversity of student views in a science classroom may be inadequate. I close by examining the implications of this view for teaching in science lessons and elsewhere, for example in religious education lessons and citizenship lessons and at primary level where subject divisions cannot be made in so clear‐cut a manner.  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