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   14367篇
  免费   211篇
  国内免费   23篇
教育   10138篇
科学研究   1541篇
各国文化   148篇
体育   1208篇
综合类   6篇
文化理论   106篇
信息传播   1454篇
  2021年   148篇
  2020年   206篇
  2019年   284篇
  2018年   398篇
  2017年   373篇
  2016年   380篇
  2015年   250篇
  2014年   331篇
  2013年   2561篇
  2012年   311篇
  2011年   332篇
  2010年   301篇
  2009年   237篇
  2008年   298篇
  2007年   263篇
  2006年   254篇
  2005年   226篇
  2004年   256篇
  2003年   241篇
  2002年   192篇
  2001年   468篇
  2000年   304篇
  1999年   263篇
  1998年   129篇
  1997年   165篇
  1996年   139篇
  1995年   133篇
  1994年   154篇
  1993年   125篇
  1992年   195篇
  1991年   198篇
  1990年   199篇
  1989年   213篇
  1988年   176篇
  1987年   167篇
  1986年   172篇
  1985年   218篇
  1984年   177篇
  1983年   156篇
  1982年   146篇
  1981年   139篇
  1980年   126篇
  1979年   174篇
  1978年   145篇
  1977年   125篇
  1976年   99篇
  1975年   116篇
  1974年   107篇
  1973年   113篇
  1971年   103篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
You are invited to Seattle for the 1977 Annual Meeting, its theme to be "Change, Comparison, and Controversy." Suggestions are made for activities in Seattle and the Pacific Northwest, including the cohost city, Vancouver, British Columbia.  相似文献   
74.
Indexing consistency in MEDLINE   总被引:3,自引:0,他引:3  
The quality of indexing of periodicals in a bibliographic data base cannot be measured directly, as there is no one "correct" way to index an item. However, consistency can be used to measure the reliability of indexing. To measure consistency in MEDLINE, 760 twice-indexed articles from 42 periodical issues were identified in the data base, and their indexing compared. Consistency, expressed as a percentage, was measured using Hooper's equation. Overall, checktags had the highest consistency. Medical Subject Headings (MeSH) and subheadings were applied more consistently to central concepts than to peripheral points. When subheadings were added to a main heading, consistency was lowered. "Floating" subheadings were more consistent than were attached subheadings. Indexing consistency was not affected by journal indexing priority, language, or length of the article. Terms from MeSH Tree Structure categories A, B, and D appeared more often than expected in the high-consistency articles; whereas terms from categories E, F, H, and N appeared more often than expected in the low-consistency articles. MEDLINE, with its excellent controlled vocabulary, exemplary quality control, and highly trained indexers, probably represents the state of the art in manually indexed data bases.  相似文献   
75.
76.
The present study examined three hypotheses regarding the consequences of early brain damage for academic achievement: First, early brain insults will have a negative impact on achievement, even in children with normal intelligence. Second, underachievement in these children will be at least partially independent of IQ (i.e., not fully accounted for by a lowering of IQ within the average range). Third, normally intelligent children with histories of brain insult will also manifest selective cognitive dysfunctions. To test these hypotheses, we compared two groups of children who had recovered from Haemophilus influenzae type b meningitis. The "complicated" group consisted of children who, as a consequence of having sustained neurologic complications during their illness, were more likely to have had brain insults. Children in the "uncomplicated" group did not have complications with their illness and were regarded as having escaped significant central nervous system (CNS) pathology. Only children with normal hearing and a prorated Full Scale IQ of at least 80 (WISC-R) were considered. Group differences on the Wide Range Achievement Test-Revised were consistent with the first two hypotheses. Although the two groups had similar Verbal IQs, the complicated group also had a lower mean Performance IQ and performed less well on perceptually demanding neuropsychological tasks. Findings suggest that learning disabilities may have selective, brain-related cognitive antecedents; but they challenge the practice of using IQ criteria for clinical diagnosis.  相似文献   
77.
78.
79.
80.
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