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   16005篇
  免费   218篇
  国内免费   8篇
教育   11690篇
科学研究   1323篇
各国文化   107篇
体育   1368篇
综合类   7篇
文化理论   137篇
信息传播   1599篇
  2021年   160篇
  2020年   247篇
  2019年   426篇
  2018年   533篇
  2017年   539篇
  2016年   478篇
  2015年   299篇
  2014年   359篇
  2013年   3056篇
  2012年   363篇
  2011年   417篇
  2010年   269篇
  2009年   247篇
  2008年   345篇
  2007年   259篇
  2006年   331篇
  2005年   218篇
  2004年   199篇
  2003年   194篇
  2002年   225篇
  2001年   332篇
  2000年   298篇
  1999年   271篇
  1998年   137篇
  1997年   164篇
  1996年   182篇
  1995年   185篇
  1994年   146篇
  1993年   170篇
  1992年   241篇
  1991年   218篇
  1990年   219篇
  1989年   246篇
  1988年   246篇
  1987年   212篇
  1986年   212篇
  1985年   222篇
  1984年   192篇
  1983年   230篇
  1982年   172篇
  1981年   162篇
  1980年   159篇
  1979年   233篇
  1978年   187篇
  1977年   169篇
  1976年   153篇
  1975年   130篇
  1974年   121篇
  1973年   128篇
  1971年   106篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
ABSTRACT

The aims of this study were to identify profiles of sedentary behaviour (SB) patterns, based on leisure-time self-reported SB modalities (screen, educative, social, and relaxing) and to evaluate changes in these profiles over 2 years among Spanish youth aged 8–18 years. Latent profile analysis (LPA), a data-driven analytic approach, was used to identify groups of boys and girls (n = 1553; 48% girls; mean±SD age: 12.56 ± 2.49 y) with distinct SB profiles using the SB modalities (time/d) as input variables. Latent transition analysis, an extension of LPA that uses longitudinal data, was used to analyse 2-year changes in these profiles. At baseline, four and three SB profiles were found among boys (labelled: screen, educative, social, and relaxing) and girls (labelled: screen/social, educative, and relaxing), respectively. Overall, more girls (range: 48%-67%) had the same profile over time, than boys (40%-52%). Participants with a screen or relaxing SB profile at baseline were more likely to have an educative profile after 2 years. Youth with a social and an educative SB profile at baseline were more likely to transition to profiles characterized by higher screen and social SB, respectively. Using a novel and person-centered approach, this study identified gender-specific SB profiles that were moderately stable over time.  相似文献   
2.
Research in Higher Education - State financial aid grant programs are commonly categorized as either need-based, merit-based, or both, but their initial eligibility requirements include many more...  相似文献   
3.
In this work, we present the first quality flaw prediction study for articles containing the two most frequent verifiability flaws in Spanish Wikipedia: articles which do not cite any references or sources at all (denominated Unreferenced) and articles that need additional citations for verification (so-called Refimprove). Based on the underlying characteristics of each flaw, different state-of-the-art approaches were evaluated. For articles not citing any references, a well-established rule-based approach was evaluated and interesting findings show that some of them suffer from Refimprove flaw instead. Likewise, for articles that need additional citations for verification, the well-known PU learning and one-class classification approaches were evaluated. Besides, new methods were compared and a new feature was also proposed to model this latter flaw. The results showed that new methods such as under-bagged decision trees with sum or majority voting rules, biased-SVM, and centroid-based balanced SVM, perform best in comparison with the ones previously published.  相似文献   
4.
5.
6.
This article describes the Engineering Professors' Conference (EPC) approach to quality assurance for Higher Education Institutions, which is currently the only formalized alternative to British Standard 5750 'Quality Systems'. The EPC approach is based on principles of quality assurance and Total Quality Management which have been developed in industry. These ideas are briefly outlined, and an opinion expressed on the interpretation and application of BSS7S0 for HE. The EPC model is explained, illustrated with example elements taken from the EPC Specification and Guidelines for Quality Assurance in Higher Education. A top-down approach to the development of an institutional quality system is described, based on a quality policy statement. Areas of activity which have an important impact on the quality of education are identified, emphasising the quality assurance requirements of academic departments. Supporting and administrative quality system requirements are also described, as these also play an important role in the quality of education. Formal quality procedures and documentation in key areas are proposed.  相似文献   
7.
8.
9.
10.
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