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   17814篇
  免费   237篇
  国内免费   17篇
教育   13066篇
科学研究   1483篇
各国文化   138篇
体育   1319篇
综合类   9篇
文化理论   114篇
信息传播   1939篇
  2021年   160篇
  2020年   264篇
  2019年   384篇
  2018年   522篇
  2017年   538篇
  2016年   490篇
  2015年   322篇
  2014年   441篇
  2013年   3520篇
  2012年   436篇
  2011年   493篇
  2010年   343篇
  2009年   329篇
  2008年   429篇
  2007年   329篇
  2006年   401篇
  2005年   263篇
  2004年   251篇
  2003年   245篇
  2002年   273篇
  2001年   387篇
  2000年   341篇
  1999年   298篇
  1998年   158篇
  1997年   185篇
  1996年   196篇
  1995年   207篇
  1994年   174篇
  1993年   198篇
  1992年   252篇
  1991年   243篇
  1990年   235篇
  1989年   265篇
  1988年   263篇
  1987年   238篇
  1986年   227篇
  1985年   246篇
  1984年   208篇
  1983年   247篇
  1982年   190篇
  1981年   176篇
  1980年   176篇
  1979年   251篇
  1978年   201篇
  1977年   175篇
  1976年   158篇
  1975年   137篇
  1974年   125篇
  1973年   132篇
  1971年   111篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
The Alfred Taubman Medical Library at the University of Michigan has offered instruction in online literature searching to third-year pharmacy students as a component of the course "Drug Information and Scientific Literature Evaluation" since 1983. In the spring of 1989, a follow-up study was conducted to assess the impact of instruction on four classes of graduates. Of a pool of 151 graduates, 90 (60%) responded to a mailed questionnaire on their use of information and computerized literature searching. The respondents were divided into four subgroups: end-user searchers, users of intermediaries, end users who used intermediaries, and those who did not use computerized literature search systems. Seventy-two percent of the respondents used some type of computerized literature searching, and 42% performed their own searches. The four subgroups differed in general computer use, familiarity with MEDLINE search terminology, information use, reasons for using or not using literature searching, and characteristics of searches (i.e., type, time frame, amount, and frequency). Training in end-user search systems appears to have had an impact on the continued use of computerized literature searching several years after the formal educational program.  相似文献   
44.
45.
Physician information seeking: improving relevance through research   总被引:1,自引:0,他引:1  
Health sciences libraries have considerable potential as resources for both formal continuing professional education, as well as the informal continuing education that results from the professional's efforts to solve problems in daily practice. While there is a growing interest in making the resources of health sciences libraries more accessible to practitioners on a routine, day-to-day basis, there also needs to be more awareness of how, when, where, and why professionals look for information in the context of practical problems. This paper reviews recent research that identifies the context in which physicians seek information and advice from external sources, the information sources that physicians access, and the factors that influence which particular sources are sought. The results indicate that physicians vary in their information needs, preferences, motivations, and strategies for seeking information. This diversity suggests that health sciences libraries, in their efforts to be more accessible, should consider "market research" to determine the needs, preferences, and use patterns of the library's targeted users. Libraries may also benefit from exploring alternative methods of improving access to their resources.  相似文献   
46.
47.
The current societal and professional context presents a variety of ethical challenges to decision makers. The importance of educational preparation for ethical decision-making and ethical leadership has been addressed in the literature of library and information science (LIS), among other professions. However, it can be quite difficult to measure the impact of professional ethics education on students. This article is based on an evaluation of published original research related to ethics education in disciplines supported by professional education, including education, nursing, allied health, journalism, social work, public health, engineering, and LIS. The study considers data related to research design, methodologies used, populations studied, approaches to measuring impact, levels of impact, and publication in the journal literature. Results indicate more extensive research in education and nursing as compared with other fields, a lack of baseline data gathering for comparison, a reliance on a limited number of data-gathering techniques, and a tendency toward studying alumni over current students  相似文献   
48.
49.
We present an overview of previous research results on the molecular phylogenetic analyses in Agaricales and its higher ranks (Agaricomycetes/Agaricomycotina/Basidiomycota) along with the most recent treatments of taxonomic systems in these taxa. Establishing phylogenetic hypotheses using DNA sequences, from which an understanding of the natural evolutionary relationships amongst clades may be derived, requires a robust dataset. It has been recognized that single-gene phylogenies may not truly represent organismal phylogenies, but the concordant phylogenetic genealogies from multiple-gene datasets can resolve this problem. The genes commonly used in mushroom phylogenetic research are summarized.  相似文献   
50.
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