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   23068篇
  免费   108篇
  国内免费   9篇
教育   16533篇
科学研究   2696篇
各国文化   139篇
体育   1160篇
综合类   6篇
文化理论   503篇
信息传播   2148篇
  2020年   117篇
  2019年   179篇
  2018年   2388篇
  2017年   2354篇
  2016年   1827篇
  2015年   282篇
  2014年   333篇
  2013年   2356篇
  2012年   434篇
  2011年   966篇
  2010年   1036篇
  2009年   609篇
  2008年   873篇
  2007年   1395篇
  2006年   255篇
  2005年   557篇
  2004年   615篇
  2003年   521篇
  2002年   271篇
  2001年   141篇
  2000年   193篇
  1999年   133篇
  1998年   95篇
  1997年   110篇
  1996年   104篇
  1995年   92篇
  1994年   113篇
  1993年   130篇
  1992年   158篇
  1991年   177篇
  1990年   163篇
  1989年   168篇
  1988年   137篇
  1987年   148篇
  1986年   161篇
  1985年   166篇
  1984年   157篇
  1983年   163篇
  1982年   131篇
  1981年   141篇
  1980年   118篇
  1979年   163篇
  1978年   155篇
  1977年   102篇
  1976年   104篇
  1975年   89篇
  1974年   79篇
  1973年   95篇
  1972年   82篇
  1970年   80篇
排序方式: 共有10000条查询结果,搜索用时 311 毫秒
91.
92.
Analysis of Statistical Question Classification for Fact-Based Questions   总被引:1,自引:0,他引:1  
Question classification systems play an important role in question answering systems and can be used in a wide range of other domains. The goal of question classification is to accurately assign labels to questions based on expected answer type. Most approaches in the past have relied on matching questions against hand-crafted rules. However, rules require laborious effort to create and often suffer from being too specific. Statistical question classification methods overcome these issues by employing machine learning techniques. We empirically show that a statistical approach is robust and achieves good performance on three diverse data sets with little or no hand tuning. Furthermore, we examine the role different syntactic and semantic features have on performance. We find that semantic features tend to increase performance more than purely syntactic features. Finally, we analyze common causes of misclassification error and provide insight into ways they may be overcome.  相似文献   
93.
Constructing a concise medical taxonomy.   总被引:2,自引:0,他引:2  
  相似文献   
94.
95.
Although the USSR and the United States had a comparable number of employees in the field of scientific information, there was a substantial difference in funding, which resulted in a lack of information support for Soviet scientists. While 90% of the publications in the United States were available almost immediately after their release, in the USSR they were delayed by 1.5 to 2 years. Since the publication of the Abstracts Journal by VINITI (AJ), its content was consistently expanding and reached its peak in 1990 (1.5 million documents per year). The next quarter of a century was characterized by a decline in both the composition of the AJ and the time required for its document coverage. The steps for restructuring VINITI activities are discussed. The focus is made on improving the limited coverage of the Russian-language part of the global flow of scientific information by Western information systems.  相似文献   
96.
The issues related to funding of public research organizations are explored. The history of scientometric information systems is outlined. The advantages and disadvantages of a bibliometric approach to financing of research organizations are analyzed. The link between the assessment of the scientific and technological potential of an institution and the optimal allocation of funds is investigated. Recommendations on how to improve the efficiency of public resources allocated for scientific research are presented.  相似文献   
97.
Modern global eco-dynamics problems are discussed. It is noted that global changes are mostly characterized by several key features, such as their multicomponent nature, as well as interactivity and nonlinearity. These features challenge various forecast estimates in such a way that the concept of forecasting has been replaced over the last few years by a much more ambiguous concept of scenarios. The vagueness of scenarios is due to the problem of global climate change. A global climate–nature–society system model is outlined.  相似文献   
98.
The current state of the Russian Science Citation Index is analyzed. Several areas for its further development identified by long-standing active users, such as data searching, refinement, and storage; current user alerts; data input with the Science Index license; patent information; and the application programming interface (API) are investigated.  相似文献   
99.
This study analyzes the predictors of 2 types of media selectivity: interest-based (i.e., choice of entertainment over politics) and partisan (i.e., choice of pro-attitudinal over counter-attitudinal or balanced news). Relying on a large survey-based experiment, we find that issue-specific engagement variables, including perceived issue understanding, issue importance, and issue attitude strength, predict interest-based and partisan selectivity above and beyond the influence of general political knowledge, news interest, and strength of political leanings. These results show that the drivers of selectivity are more complex than general political attributes; rather, they are contextual and reflect people’s engagement with particular issues.  相似文献   
100.
There are three models for community archives in China. The first one is where community archives are kept in government-funded/government-established museums or archives. The second is where community archives are kept by scholarly organizations such as universities. The third involves the community establishing its own archive. This last model is very unusual in China. The PiCun Culture and Art Museum of Migrant Labor (PCMML) provides an example of this model as it is the only independent community archives focusing on migrant workers in China. This paper explores the emergence and development of PCMML, its impact on community members and challenges faced including funding and staffing, but also those unique to China—PCMML is greatly influenced by a range of national and local government policies and regulations. Conclusions are that survival strategies for independent community archives in China are dependent on three dimensions: the community itself, society and the government. Cultural consciousness of the community is the premise for the establishment and sustainability of independent community archives, and independent community archives can be the public space to cultivate cultural consciousness of community members and thus activates community members’ agency to document, preserve and disseminate their own history. At the same time, independent community archives also need to engage with broader society to avoid involution and gain support and understanding. Independent community archives are constrained by government policies and regulations, so it is essential for them to develop strategic relationships with government.  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