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   35167篇
  免费   419篇
  国内免费   15篇
教育   25735篇
科学研究   3214篇
各国文化   234篇
体育   2274篇
综合类   14篇
文化理论   567篇
信息传播   3563篇
  2022年   183篇
  2021年   284篇
  2020年   412篇
  2019年   657篇
  2018年   2953篇
  2017年   2876篇
  2016年   2290篇
  2015年   590篇
  2014年   821篇
  2013年   4718篇
  2012年   891篇
  2011年   1401篇
  2010年   1340篇
  2009年   934篇
  2008年   1201篇
  2007年   1650篇
  2006年   506篇
  2005年   800篇
  2004年   838篇
  2003年   731篇
  2002年   496篇
  2001年   492篇
  2000年   426篇
  1999年   364篇
  1998年   212篇
  1997年   228篇
  1996年   244篇
  1995年   241篇
  1994年   187篇
  1993年   203篇
  1992年   325篇
  1991年   310篇
  1990年   300篇
  1989年   300篇
  1988年   257篇
  1987年   303篇
  1986年   270篇
  1985年   306篇
  1984年   247篇
  1983年   211篇
  1982年   192篇
  1981年   164篇
  1980年   154篇
  1979年   259篇
  1978年   183篇
  1977年   170篇
  1976年   155篇
  1975年   141篇
  1974年   147篇
  1971年   140篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
Abstract

In an economic climate when colleges can no longer presume that legislators see institutions of higher learning as tacit public goods, institutions around the country are facing budget cuts. This article presents a case study of the experience of a mid-sized public state university and its Library in a budget crisis undergoing a university-wide program prioritization process. The authors review the process of writing three reports on the Library’s value, along with the approach to engaging staff in the process including a retreat. This article raises questions about what every library should consider assessing and provide tools for libraries navigating similar terrain.  相似文献   
14.
A significant number of archaeological finds of the 13th–16th century from the Tuscan sites of Germagnana and Gambassi in Valdelsa—FI, was studied by different physico-chemical investigations (SEM–EDS, ICP, Mössbauer spectroscopy, XRD, XRF, TG-DTA) in order to contribute to clarify the production methodology and the pre-industrial glass manufacture technology. The studied samples are mainly non-vitreous finds as production waste, refractory materials, crucibles and raw materials; also vitreous finds as frits, skims, glasses (glass masses, glass working waste and finished products) have been taken into consideration. The obtained petrographic and physico-chemical data strongly suggest that both Gambassi and Germagnana glass manufactures were strictly connected with the sources of vitrifiable materials, situated in Tuscan sand quarries. In particular a comparison between sands from the neighbouring quarries and appropriate finds of the two archaeological sites evidences that the employed vitrifiable materials possibly belong to La Casina La Cava resort. The archaeological classification, based on macroscopic observation and stratigraphic position, was compared and verified with the scientific classification of the examined finds of Germagnana and Gambassi sites based on their composition, morphology and physico-chemical properties.  相似文献   
15.
Continuous observation of the physical activity of 56 preadolescent children was conducted in four regions of England from October 1988 to July 1989. Observations were undertaken during school break times, lunch times, and physical education lessons, as well as during the children's free time. Of total time observed, the children spent 32.4% of it engaged in moderate to vigorous physical activity (MVPA). Children were shown to be most active during school breaks and least active during free time at home. However, it is thought that cardiorespiratory benefits are best achieved by participation in sustained periods of MVPA. Only 8 (14%) of the 56 children were observed to participate in MVPA for sustained periods of 20 min or longer. A random sample of 55 physical education lessons was observed. Only 6 children engaged in MVPA for sustained periods of 5 min or more, and no children participated in MVPA for 10 min or longer. The implications of these results are that, although the children engaged in a reasonable amount of MVPA, it may not have been sustained for periods of sufficient length to produce a cardiovascular training response. Consideration is given to ways of promoting lifelong involvement in physical activity.  相似文献   
16.
17.
18.
19.
20.
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