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   17032篇
  免费   248篇
  国内免费   120篇
教育   11781篇
科学研究   2111篇
各国文化   115篇
体育   1570篇
综合类   11篇
文化理论   160篇
信息传播   1652篇
  2022年   123篇
  2021年   147篇
  2020年   256篇
  2019年   420篇
  2018年   561篇
  2017年   502篇
  2016年   517篇
  2015年   303篇
  2014年   398篇
  2013年   2912篇
  2012年   341篇
  2011年   374篇
  2010年   292篇
  2009年   280篇
  2008年   283篇
  2007年   314篇
  2006年   298篇
  2005年   285篇
  2004年   267篇
  2003年   263篇
  2002年   257篇
  2001年   270篇
  2000年   280篇
  1999年   282篇
  1998年   155篇
  1997年   164篇
  1996年   192篇
  1995年   181篇
  1994年   143篇
  1993年   148篇
  1992年   223篇
  1991年   231篇
  1990年   237篇
  1989年   266篇
  1988年   214篇
  1987年   230篇
  1986年   222篇
  1985年   263篇
  1984年   233篇
  1983年   213篇
  1982年   182篇
  1981年   171篇
  1980年   161篇
  1979年   250篇
  1978年   197篇
  1977年   181篇
  1976年   150篇
  1975年   133篇
  1974年   155篇
  1973年   139篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
The purpose of this investigation was to describe the morphological parameters that characterize elite age group divers. Comparisons are made to normative age group data from the Coquitlam Growth Study and the constancy of important characteristics from age group to age group is examined. Data were collected on 27 male and 28 female elite divers who participated in the 1990 North American Age Group Diving Championships. Body build, body composition and skinfold corrected diameters were determined from 36 anthropometric parameters and analysed by ANOVA, t-test and Phantom z-scores procedures. All age groups except the 14- to 15-year-old males were significantly (P < or = 0.05) shorter than their norms but recorded higher androgyny index values. The estimated relative muscle mass increased significantly (P < or = 0.05) with age for males at all ages (40.8-46.3%). The 16- to 18-year-old females had a significantly (P < or = 0.05) larger relative muscle component compared to the younger age groups (40.1-38.4%). When normalized for height, active tissue development of the extremities was comparable between the sexes except in the forearm. The results indicate that at all age levels short stature is an important characteristic for divers. Analysis of regional active tissue development provides further insight into sport-specific prerequisites for success at elite levels.  相似文献   
33.
34.
35.
36.
This paper considers the background of the Library-Bibliographic Classification as the national classification system of Russia, and its history and application in the USSR. It gives the general characteristic of the LBC structure, content and system of designations, as well as the state of its present updating.  相似文献   
37.
38.
39.
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   
40.
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