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   48338篇
  免费   1894篇
  国内免费   28篇
  2020年   530篇
  2019年   600篇
  2018年   781篇
  2017年   832篇
  2016年   914篇
  2015年   701篇
  2014年   793篇
  2013年   3869篇
  2012年   1448篇
  2011年   1531篇
  2010年   964篇
  2009年   927篇
  2008年   1298篇
  2007年   1218篇
  2006年   1107篇
  2005年   1014篇
  2004年   990篇
  2003年   971篇
  2002年   1007篇
  2001年   1383篇
  2000年   1368篇
  1999年   997篇
  1998年   543篇
  1997年   508篇
  1992年   872篇
  1991年   829篇
  1990年   826篇
  1989年   824篇
  1988年   755篇
  1987年   736篇
  1986年   777篇
  1985年   821篇
  1984年   711篇
  1983年   673篇
  1982年   489篇
  1981年   536篇
  1979年   705篇
  1978年   565篇
  1977年   502篇
  1976年   476篇
  1975年   655篇
  1974年   758篇
  1973年   707篇
  1972年   646篇
  1971年   589篇
  1970年   538篇
  1969年   630篇
  1968年   700篇
  1967年   649篇
  1966年   635篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Kinetic subjective contours   总被引:2,自引:0,他引:2  
  相似文献   
952.
953.
Interference and facilitation in short-term memory for odors   总被引:2,自引:0,他引:2  
  相似文献   
954.
This study was designed to determine possible differences in the cognitive, perceptual, and personal-social development of prematurely and maturely born 3-yr.-olds which might foreshadow later learning problems. The subjects were 40 prematurely born graduates of a neonatal intensive care unit (birth weight less than 2,500 gm, less than 37 wk. gestation) matched on the pair-level with full-term controls on sex, race, post-conceptual age, and socioeconomic background. All subjects were singletons and parity was matched at the group level. No differences were found between the groups on tests of higher mental processes including the General Cognitive, Verbal, Quantitative, and Memory Scales of the McCarthy Scales of Children's Abilities, and researcher-devised measures of problem-solving competence. No differences in parental reports of personal-social development were noted. Prematures did not perform as well as controls on perceptual performance tasks, and this difference was interpreted as reflecting relatively impaired visual-motor coordination.  相似文献   
955.
This annotated listing is of group reports pertaining to therapeutic strategies utilized with infants and young children who have cerebral palsy. The studies are organized by type of design used.  相似文献   
956.
In a previous experiment, Allen found no release from proactive inhibition using the Brown-Peterson procedure in a group who were shifted from recalling colors to recalling the names of colors. The lack of release suggests that colors and color names are encoded in similar ways. It was argued that the similarity of encoding might have been caused by the procedure of requiring the subjects to say out loud the names of the colors at the time of stimulus presentation and recall. In the present experiment, a procedure was devised that eliminated the need for verbalization of the colors. The same pattern of results was obtained, namely, release from proactive inhibition in the group shifted from recalling color names to colors but not in the group shifted in the opposite direction. It was concluded that if subjects encode colors as a verbal label, then this encoding strategy is not caused by the procedure of requiring the subjects to verbalize the colors.  相似文献   
957.
Previous research aimed at quantifying and reducing the decrements encountered in performing manual tasks in cold weather has not described the relationships between task characteristics and cold-induced impairments. The amount of decrement and, often times, the optimal means for reducing the decrement, appear to be task-specific. The research reported here is one in a series of studies formulated to explore those relationships. The strategy is to use tasks from the battery developed by Fleishman (1967) to measure the factorially 'pure' abilities needed to perform all manual tasks. 24 U.S. Marines performed this battery of nine tasks across a range of cold temperatures. To determine if the decrement due to wearing gloves might be less than the decrement due to cold hands as the air temperature decreased, performance on the battery of tasks was measured with and without gloves. Only three of the tasks (abilities) were affected by cold temperatures, and the amount of decrement increased as the air temperature decreased. Three tasks deteriorated due to wearing of gloves, two of those affected by cold and one other. Temperature affected performance independently of the glove effect. Half of the subjects did not complete bare-handed testing at -18 degrees C (approximately 20 min.), indicating this is the lower end of the temperature range in which bare-handed performance for more than a few minutes is practical.  相似文献   
958.
959.
960.
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