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   8693篇
  免费   133篇
  国内免费   7篇
教育   6356篇
科学研究   518篇
各国文化   165篇
体育   717篇
综合类   3篇
文化理论   133篇
信息传播   941篇
  2022年   51篇
  2021年   77篇
  2020年   154篇
  2019年   214篇
  2018年   291篇
  2017年   313篇
  2016年   304篇
  2015年   229篇
  2014年   244篇
  2013年   1932篇
  2012年   232篇
  2011年   238篇
  2010年   213篇
  2009年   189篇
  2008年   281篇
  2007年   219篇
  2006年   217篇
  2005年   196篇
  2004年   151篇
  2003年   184篇
  2002年   167篇
  2001年   133篇
  2000年   120篇
  1999年   115篇
  1998年   109篇
  1997年   113篇
  1996年   120篇
  1995年   123篇
  1994年   120篇
  1993年   100篇
  1992年   112篇
  1991年   108篇
  1990年   102篇
  1989年   95篇
  1988年   86篇
  1987年   73篇
  1986年   66篇
  1985年   74篇
  1984年   66篇
  1983年   78篇
  1982年   76篇
  1981年   81篇
  1980年   83篇
  1979年   77篇
  1978年   57篇
  1977年   46篇
  1976年   54篇
  1975年   43篇
  1974年   42篇
  1971年   31篇
排序方式: 共有8833条查询结果,搜索用时 0 毫秒
1.
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   
2.
3.
4.
5.
6.
This study examined the cost and performance of six commercial document suppliers accessible via OCLC, and comapared their service to that of traditional interlibrary loan (ILL). Results indicated that, while commercial firms cannot be recommended as a wholesale replacement for ILL, they can add much-needed flexibility to a library's overall plan for document delivery.  相似文献   
7.
The authors report on a self‐completed questionnaire study from a North Yorkshire based general practice regarding the information needs of its clinicians. The work was carried out with a particular focus on the practice library, and the findings identified that a new approach to maintaining and developing the library was needed. The literature regarding the information needs of primary care clinicians and the role of practice libraries is considered, and compared to those of the clinicians at the practice. Discussion follows on how a collaborative project was set up between the practice and a librarian based at the local NHS Trust library in order to improve the existing practice library. Difficulties encountered and issues unique to the project are explored, including training implications presented by the implementation of electronic resources. Marketing activities implemented are discussed, how the library will operate in its new capacity, and how ongoing support and maintenance of the library will be carried out. It is concluded that although scepticism still exists regarding librarian involvement in practice libraries, collaboration between clinicians and librarians is an effective approach to the successful development and maintenance of a practice library, and recommendations are therefore made for similar collaborative work.  相似文献   
8.
Collaboration in research activity is now the rule not the exception. It is encouraged by government, funding bodies and research councils. However, the concept of collaboration is difficult to define. It occurs at many different levels, driven by a complex research system-policy dynamic. Three different models of collaboration – inter-personal, team and corporate – are identified, each with their own rationale, structure, benefits and costs. The paper examines the institutional implications of these models. It argues that institutions and individual researchers conceptualise and operationalise research collaboration in different ways. Although vital to institutional mission, collaborative research is rarely mapped by senior managers with any precision. In general, institutional approaches to the management of collaborative research lag behind the policy rhetoric. The paper concludes with an overview of the key dilemmas for institutional strategists and policy makers posed by the shift towards more collaborative approaches to research.  相似文献   
9.
10.
Co-production occurs when two or more institutions contribute funds and labour to the processes of making course components for distance teaching. The author summarises reasons for international co-production of multimedia distance-teaching courses and provides a checklist of questions that should be considered before entering upon such co-production.
The second half of the article consists of a composite case study based on the UK's Open University experience of international co-production. The paper ends with three questions: Is international co-production of this kind worth trying? Can the chances of success be made high enough by careful planning to justify risking capital in such ventures? Are other forms of collaboration more likely to be cost-effective?  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