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   29400篇
  免费   219篇
  国内免费   25篇
教育   20991篇
科学研究   3185篇
各国文化   154篇
体育   1958篇
综合类   9篇
文化理论   537篇
信息传播   2810篇
  2021年   180篇
  2020年   265篇
  2019年   396篇
  2018年   2683篇
  2017年   2593篇
  2016年   2060篇
  2015年   457篇
  2014年   602篇
  2013年   3235篇
  2012年   645篇
  2011年   1169篇
  2010年   1214篇
  2009年   758篇
  2008年   1026篇
  2007年   1509篇
  2006年   412篇
  2005年   689篇
  2004年   751篇
  2003年   648篇
  2002年   398篇
  2001年   350篇
  2000年   361篇
  1999年   326篇
  1998年   170篇
  1997年   213篇
  1996年   214篇
  1995年   158篇
  1994年   192篇
  1993年   153篇
  1992年   307篇
  1991年   272篇
  1990年   251篇
  1989年   274篇
  1988年   237篇
  1987年   213篇
  1986年   238篇
  1985年   241篇
  1984年   188篇
  1983年   220篇
  1982年   176篇
  1981年   182篇
  1980年   155篇
  1979年   258篇
  1978年   171篇
  1977年   166篇
  1976年   164篇
  1975年   126篇
  1974年   146篇
  1973年   115篇
  1971年   111篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
Working Graphs     
  相似文献   
62.
63.
64.
This paper examines end-user, online searching using data from a questionnaire mailed to 150 Canadian health professionals in practice settings. The response rate was 83% (n = 124). The data provide a demographic profile of early adopters of end-user searching in the health care community. Positive correlations with the user's level of implementation of end-user searching were found for the following variables: amount of time spent in research activities, amount of system training received, and use of Medical Subject Headings (MeSH). There was a negative association between the amount of time spent in patient care and implementation level. General practitioners and family physicians had lower implementation levels than physicians in other specialties. Successful implementers were more likely to be computer literate and to place a high value on formal information sources such as books, journals, and libraries. Health professionals using so-called "user-friendly" or menu-based software had lower levels of personal commitment to using online databases, as measured by a combination of continuance of use, willingness to pay personally, type of recommendations made to colleagues, and hardware ownership.  相似文献   
65.
66.
Acquiring both published and unpublished documents produced in Africa is, generally, a difficult task due to the existing poor state of bibliographic control and the publishing industry. It is even more difficult to obtain unpublished documents in a specialized area of study such as demography--a diffuse area which cuts across several disciplines. This paper discusses the problems encountered on acquisition trips to some African countries to acquire unpublished population material. To help solve the problems, the Population Association of Africa must persuade its members to send copies of their publications to population libraries and documentation centers in their individual countries for dissemination to the other users in Africa. The various organizations and institutions in Africa engaged in the teaching and research of population studies should have an agreement to exchange copies of their theses. The Economic Commission for Africa (ECA) and the Organization of African Unity (OAU) should make representations to the various African member countries on the need to disseminate the results of vital censuses and surveys conducted. Finally, the Population Information Network for Africa (POPIN-AFRICA) with its coordinating unit at the population division of ECA should ensure that all the nodes of the network have the financial and other resources to be able to acquire the relevant documents needed for their operations.  相似文献   
67.
Computers are integral to medical practice, education, and research. While medical students learn computer skills during their training, many practicing physicians do not have the same computer experience. To familiarize this group with the exciting developments in medical informatics, the Himmelfarb Health Sciences Library and Department of Computer Medicine at the George Washington University Medical Center organized a workshop "Introducing Your Office Computer!" for attending physicians. The workshop featured a short lecture/video presentation on computer applications in medicine followed by a "computer fair" of five computer applications. Eleven physicians attended the workshop. Feedback was very positive; many called later to request more detailed instructions on using the programs demonstrated. It was a valuable experience for the staff, and new bridges were built between departments and clients.  相似文献   
68.
This study was designed to examine children's attitudes toward the role of sports in determining social status, as well as the activities in which children prefer to participate. A total of 227 boys and 251 girls in Grades 4, 5, and 6 completed a questionnaire to determine which criteria were most important in determining personal, female, and male popularity. Personal popularity was answered by the girls and boys according to "what would make you well liked by your classmates." Female and male popularity was determined by asking both girls and boys to decide "what would make (girls, for female subjects, and boys, for male subjects) well liked by your classmates." A comparison of results from the Buchanan, Blankenbaker, and Cotten (1976) investigation and the present study indicated that, in the last 15 years, appearance has become more important and academic achievement less important in determining personal popularity for girls. For boys, the comparison revealed that sports have become more important and academic achievement less important in determining personal popularity. Boys reported sports to be the most important determinant of personal and male popularity and appearance as the most important determinant of female popularity. Sports and appearance became more important for boys with each higher grade level. Girls reported appearance to be the most important determinant of personal, male, and female popularity. For girls, appearance became more important with each higher grade level. A comparison of results from the Buchanan et al. (1976) and the present study indicated that the activities in which girls and boys preferred to participate have changed.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
69.
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   
70.
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