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   912篇
  免费   20篇
  国内免费   3篇
教育   768篇
科学研究   19篇
各国文化   11篇
体育   26篇
综合类   1篇
文化理论   2篇
信息传播   108篇
  2023年   4篇
  2022年   10篇
  2021年   10篇
  2020年   12篇
  2019年   25篇
  2018年   27篇
  2017年   33篇
  2016年   40篇
  2015年   28篇
  2014年   39篇
  2013年   187篇
  2012年   34篇
  2011年   28篇
  2010年   36篇
  2009年   30篇
  2008年   28篇
  2007年   26篇
  2006年   19篇
  2005年   14篇
  2004年   16篇
  2003年   13篇
  2002年   21篇
  2001年   19篇
  2000年   15篇
  1999年   28篇
  1998年   14篇
  1997年   11篇
  1996年   21篇
  1995年   10篇
  1994年   11篇
  1993年   13篇
  1992年   11篇
  1991年   8篇
  1990年   8篇
  1989年   12篇
  1988年   7篇
  1987年   8篇
  1986年   9篇
  1985年   6篇
  1983年   4篇
  1982年   3篇
  1981年   2篇
  1980年   4篇
  1979年   4篇
  1978年   7篇
  1977年   2篇
  1975年   4篇
  1974年   2篇
  1969年   2篇
  1968年   2篇
排序方式: 共有935条查询结果,搜索用时 8 毫秒
51.
User involvement is assumed to be beneficial to innovation processes. Intermediary user organisations contribute to articulating societal demands for innovations. However, the learning processes inside these organisations are still not understood well. Therefore, this paper empirically investigates intermediaries using an event history approach. It yields characteristic learning mechanisms, e.g. concerning the management of expectations or actively building a case. If intermediaries overcome challenges regarding positioning, representation and the level of proactivity, they can play a precarious role in demand articulation in the context of new technologies.  相似文献   
52.
This column reports the results of a survey conducted of medical librarian participants in medical informatics training at the University of Pittsburgh. This small study was undertaken in order to identify issues in training different kinds of library and information science practitioners in medical informatics.  相似文献   
53.
54.
This paper investigates the number of expansion terms to use in automatic query expansion by examining the behavior of eight retrieval systems participating in the NRRC Reliable Information Access Workshop. The results demonstrate that current systems are able to obtain nearly all of the benefit of using a fixed number of expansion terms per topic, but significant additional improvement is possible if systems were able to accurately select the best number of expansion terms on a per topic basis. When optimizing average effectiveness as measured by mean average precision, using a fixed number of terms increases the score a large amount for a small number of topics but has little effect for most topics. The analysis further suggests that when a topic is helped by automatic feedback, the increase is from a set of terms that reinforce each other rather than from the system finding a single excellent term.  相似文献   
55.
56.
Those entering the world of publishing standards for the first time may find it a baffling alphabet soup—with NISO, ANSI, BISG, IEEE, NIST, and ANSC floating on a broth bubbling with activity. Jacob and Rings sort out the acronyms, explaining what each of these groups does and how they interact. Mary Ellen L. Jacob, vice president for library planning at OCLC, is responsible for strategic planning activities regarding libraries and library services. Mrs. Jacob is also the board chair of the National Information Standards Committee. Deborah L. Rings, information analyst for library planning at OCLC, is responsible for identifying trends and factors relative to the library and information science areas, and for assessing their impact and potential impact on OCLC and its strategic planning processes.  相似文献   
57.
58.
59.
Abstract

The aim of this study was to understand the role that agricultural consultants in New Zealand were undertaking in the Research, Development and Extension (RD&E) system—and in particular in relation to environmental extension. New Zealand does not have a public extension service and hence there is a strong reliance on consultants and regional councils for environmental management information and advice. As they are independent of the formal RD&E system there is no guarantee that RD&E outcomes are reaching farmers, nor that effective environmental extension is occurring. The study used a combination of case studies, phone interviews with informed persons and a national web survey to explore the role of the consultant. The study found that agricultural consultants are playing an important role in working with farmers to improve agricultural production. There are, however, indications that gaps have developed over time between agricultural consultants and the agricultural research sector which limit the effectiveness of the RD&E system. Agricultural consultants are playing a minimal role in proactive environmental extension because insufficient market forces are driving this role. The paper suggests that a national database of agricultural consultants could improve the flow of tailored information between research and agricultural consultants and also suggests mechanisms where consultants could be better integrated into the RD&E system and provide feedback to research programs. Market failure in the area of environmental extension could be addressed by publicly funded incentive programs.  相似文献   
60.

This article assesses the quality of 12 American doctoral programs by counting the number of publications of their Ph.D. graduates in a large number of criminology and criminal justice journals, and in 20 more “academic” journals. While half of the Ph.D. graduates had no publications, the 4 percent who were the most productive (the “stars”) accounted for one third of all journal articles. Publication rates up to graduation predicted publication rates after graduation. The University of Maryland, Michigan State University, the University of California at Irvine, Florida State University, and Sam Houston State University had the most productive Ph.D. graduates in academic journals. There was a significant correlation between the productivity of a program's Ph.D. graduates and the productivity of its faculty members. The academic publication rate was influenced most by prevalence (the percentage of Ph.D.s with at least one publication), rather than by the percentage of “stars” or the frequency of publications.  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