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   20954篇
  免费   117篇
  国内免费   6篇
教育   15055篇
科学研究   2335篇
各国文化   323篇
体育   1062篇
综合类   5篇
文化理论   452篇
信息传播   1845篇
  2021年   87篇
  2020年   121篇
  2019年   183篇
  2018年   2409篇
  2017年   2355篇
  2016年   1827篇
  2015年   280篇
  2014年   298篇
  2013年   1703篇
  2012年   425篇
  2011年   958篇
  2010年   1035篇
  2009年   608篇
  2008年   884篇
  2007年   1401篇
  2006年   241篇
  2005年   557篇
  2004年   637篇
  2003年   492篇
  2002年   249篇
  2001年   162篇
  2000年   201篇
  1999年   160篇
  1998年   91篇
  1997年   100篇
  1996年   78篇
  1995年   69篇
  1994年   68篇
  1993年   85篇
  1992年   140篇
  1991年   146篇
  1990年   143篇
  1989年   153篇
  1988年   116篇
  1987年   109篇
  1986年   114篇
  1985年   152篇
  1984年   121篇
  1983年   101篇
  1982年   93篇
  1981年   73篇
  1980年   80篇
  1979年   128篇
  1978年   83篇
  1977年   83篇
  1976年   77篇
  1974年   84篇
  1973年   73篇
  1971年   69篇
  1968年   65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.
Editorial     
B. Sury 《Resonance》2018,23(7):723-725
  相似文献   
5.
6.
7.
8.
9.
ABSTRACT

This article offers a textual analysis and semiotic reading of the Rich Kids of Tehran's (RKOT’s) Instagram page. Contributing to scholarship on Iranian youth media practices, this article interrogates how the RKOT navigate urban and rural space to engage in everyday processes of resistance against global and local systemic oppression. Grounding their visual representations on Instagram in historical and cultural context, the author questions how and when quotidian actions are transformed into political transgressions when posted on social media. This article emphasizes the RKOT's agency in shaping their brand by analyzing representations of gender performance, intertextuality, and national identity on Instagram.  相似文献   
10.
In the IR field it is clear that the value of a system depends on the cost and benefit profiles of its users. It would seem obvious that different users would prefer different systems. In the TREC-9 filtering track, systems are evaluated by a utility measure specifying a given cost and benefit. However, in the study of decision systems it is known that, in some cases, one system may be unconditionally better than another. In this paper we employ a decision theoretic approach to find conditions under which an Information Filtering (IF) system is unconditionally superior to another for all users regardless of their cost and benefit profiles.It is well known that if two IF systems have equal precision the system with better recall will be preferred by all users. Similarly, with equal recall, better precision is universally preferred. We confirm these known results and discover an unexpected dominance relation in which a system with lower recall will be universally preferred provided its precision is sufficiently higher.  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