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   16682篇
  免费   82篇
  国内免费   15篇
教育   12783篇
科学研究   1497篇
各国文化   55篇
体育   798篇
综合类   12篇
文化理论   441篇
信息传播   1193篇
  2022年   40篇
  2021年   65篇
  2020年   102篇
  2019年   179篇
  2018年   2355篇
  2017年   2265篇
  2016年   1747篇
  2015年   227篇
  2014年   272篇
  2013年   1179篇
  2012年   371篇
  2011年   832篇
  2010年   977篇
  2009年   567篇
  2008年   785篇
  2007年   1284篇
  2006年   183篇
  2005年   491篇
  2004年   549篇
  2003年   454篇
  2002年   246篇
  2001年   92篇
  2000年   148篇
  1999年   83篇
  1998年   79篇
  1997年   80篇
  1996年   78篇
  1995年   63篇
  1994年   67篇
  1993年   62篇
  1992年   45篇
  1991年   81篇
  1990年   53篇
  1989年   46篇
  1988年   38篇
  1987年   49篇
  1986年   46篇
  1985年   43篇
  1984年   48篇
  1983年   39篇
  1982年   34篇
  1981年   37篇
  1980年   30篇
  1979年   25篇
  1978年   29篇
  1977年   37篇
  1976年   29篇
  1975年   21篇
  1974年   22篇
  1971年   12篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
David Kaldewey 《Minerva》2018,56(2):161-182
This article analyzes the concept of “grand challenges” as part of a shift in how scientists and policymakers frame and communicate their respective agendas. The history of the grand challenges discourse helps to understand how identity work in science and science policy has been transformed in recent decades. Furthermore, the question is raised whether this discourse is only an indicator, or also a factor in this transformation. Building on conceptual history and historical semantics, the two parts of the article reconstruct two discursive shifts. First, the observation that in scientific communication references to “problems” are increasingly substituted by references to “challenges” indicates a broader cultural trend of how attitudes towards what is problematic have shifted in the last decades. Second, as the grand challenges discourse is rooted in the sphere of sports and competition, it introduces a specific new set of societal values and practices into the spheres of science and technology. The article concludes that this process can be characterized as the sportification of science, which contributes to self-mobilization and, ultimately, to self-optimization of the participating scientists, engineers, and policymakers.  相似文献   
2.
3.
Letters     
  相似文献   
4.
Ronald Barnett's modern classic Realizing the University in an Age of Supercomplexity (published December 1999), has had a crucial impact internationally on the field of Higher Education research and development since the book was published now nearly 20 years ago. Bridging an academic oeuvre across almost 30 years with close to 30 published volumes, Realizing the University in an Age of Supercomplexity plays an important role in the development and transformation of Barnett's social theory of Higher Education into a social philosophy of Higher Education. In the book Barnett performs an important move from a focus on knowledge and epistemology to a focus on being and ontology in relation to Higher Education practices. Barnett shifts his fundamental perspective and view on the relation between universities and the wider society from one of caution and worry to a perspective of hope and vision that fully embraces the future of Higher Education. This way, Realizing the University in an Age of Supercomplexity has not only paved the way for Barnett's own development of a social philosophy of Higher Education, but also contributed invaluably to the rise and maturing of philosophy of Higher Education as a research field in its own right.  相似文献   
5.
6.
7.
8.
9.
10.
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   
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