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   31531篇
  免费   403篇
  国内免费   21篇
教育   22608篇
科学研究   2427篇
各国文化   415篇
体育   2874篇
综合类   10篇
文化理论   334篇
信息传播   3287篇
  2021年   305篇
  2020年   490篇
  2019年   739篇
  2018年   998篇
  2017年   956篇
  2016年   938篇
  2015年   609篇
  2014年   762篇
  2013年   6018篇
  2012年   698篇
  2011年   743篇
  2010年   606篇
  2009年   604篇
  2008年   721篇
  2007年   629篇
  2006年   602篇
  2005年   535篇
  2004年   530篇
  2003年   477篇
  2002年   477篇
  2001年   587篇
  2000年   614篇
  1999年   542篇
  1998年   350篇
  1997年   352篇
  1996年   412篇
  1995年   365篇
  1994年   367篇
  1993年   309篇
  1992年   454篇
  1991年   466篇
  1990年   440篇
  1989年   453篇
  1988年   416篇
  1987年   395篇
  1986年   388篇
  1985年   434篇
  1984年   350篇
  1983年   372篇
  1982年   310篇
  1981年   321篇
  1980年   337篇
  1979年   417篇
  1978年   311篇
  1977年   280篇
  1976年   254篇
  1975年   223篇
  1974年   218篇
  1973年   208篇
  1971年   201篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
  • Scientific publication has been a key part of the scientific method since the inception of Philosophical Transactions in 1665.
  • The scientific publications industry has grown exponentially along with science, incorporating technological innovations along the way, and adapting journal processes and practices to changing needs of science as it matured.
  • Of all the technological innovations over more than 300 years, the move to online journals may be the most significant, making open access to content practical for the first time.
  • The open‐access movement is disrupting the economics of journal publishing, which is hoped will make the industry more competitive: the ability of the publications industry to adapt to open access will be a measure of its resilience.
  • The demand for articles published in reputable journals continues to grow as readers trust the credibility of peer reviewed journal articles, and good authors value the prestige of publishing in the best journals.
  • It is difficult to predict what new functionalities may be included in articles of the future or what additional services publishers and editors will provide, but there is every reason to believe that scientific journal articles are here to stay.
  相似文献   
2.
ABSTRACT

This forum brings together food, (in)security, and communication. The authors participating in this forum center communication as both process and tool for understanding, mitigating, and making meaning of food (in)security. The nine authors together discuss the role of communication in food (in)security, the central challenges for scholars and practitioners working on food (in)security, and the creative possibilities and impacts influencing the future of food (in)security. The forum produces a call for applied scholars to re-imagine communication frameworks in order to make meaningful differences in their communities.  相似文献   
3.
The purpose of this article was to systematically review the available research on learner characteristics that influence the treatment effectiveness of early literacy interventions. Meta‐analytic procedures were applied to a total of 30 studies that met the inclusionary and exclusionary criteria. Mean average effect sizes were computed for seven primary learner characteristic categories: (1) rapid naming, (2) alphabetic principle, (3) phonological awareness, (4) problem behavior, (5) memory, (6) IQ, and (7) demographic. The primary learner characteristics that influenced the treatment responsiveness of early literacy interventions were, in order of magnitude, rapid naming, problem behavior, phonological awareness, alphabetic principle, memory, IQ, and demographics. With the exception of the demographic category, the obtained effect sizes for the primary learner characteristics were moderately large. The demographic primary learner characteristic (i.e., disability, ethnicity, grade‐level status) of children was not statistically (p < 0.05) distinct from zero. The findings, limitations, and future research needs are discussed.  相似文献   
4.
5.
Measuring Search Engine Quality   总被引:12,自引:3,他引:9  
The effectiveness of twenty public search engines is evaluated using TREC-inspired methods and a set of 54 queries taken from real Web search logs. The World Wide Web is taken as the test collection and a combination of crawler and text retrieval system is evaluated. The engines are compared on a range of measures derivable from binary relevance judgments of the first seven live results returned. Statistical testing reveals a significant difference between engines and high intercorrelations between measures. Surprisingly, given the dynamic nature of the Web and the time elapsed, there is also a high correlation between results of this study and a previous study by Gordon and Pathak. For nearly all engines, there is a gradual decline in precision at increasing cutoff after some initial fluctuation. Performance of the engines as a group is found to be inferior to the group of participants in the TREC-8 Large Web task, although the best engines approach the median of those systems. Shortcomings of current Web search evaluation methodology are identified and recommendations are made for future improvements. In particular, the present study and its predecessors deal with queries which are assumed to derive from a need to find a selection of documents relevant to a topic. By contrast, real Web search reflects a range of other information need types which require different judging and different measures.  相似文献   
6.
What are typical requirements in graduate measurement programs? How d o programs in measurement and research methods differ?  相似文献   
7.
8.
Gordon  R. S.  Franklin  K. L.  Baker  J.  Davies  B. 《Sports Engineering》2004,7(3):131-138
Sports Engineering - A Monark cycle ergometer is a device globally used in physiological studies to measure the work and energy levels of exercising humans. In this paper a rope-braked cycle...  相似文献   
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