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   36590篇
  免费   701篇
  国内免费   6篇
  37297篇
  2020年   468篇
  2019年   593篇
  2018年   758篇
  2017年   755篇
  2016年   840篇
  2015年   555篇
  2014年   682篇
  2013年   3011篇
  2012年   1206篇
  2011年   1234篇
  2010年   721篇
  2009年   810篇
  2008年   1036篇
  2007年   991篇
  2006年   909篇
  2005年   791篇
  2004年   780篇
  2003年   718篇
  2002年   724篇
  2001年   1091篇
  2000年   1107篇
  1999年   806篇
  1998年   373篇
  1997年   352篇
  1995年   339篇
  1992年   657篇
  1991年   614篇
  1990年   598篇
  1989年   574篇
  1988年   563篇
  1987年   511篇
  1986年   517篇
  1985年   559篇
  1984年   472篇
  1983年   438篇
  1982年   351篇
  1979年   502篇
  1978年   355篇
  1977年   337篇
  1976年   347篇
  1975年   379篇
  1974年   457篇
  1973年   481篇
  1972年   410篇
  1971年   353篇
  1970年   328篇
  1969年   342篇
  1968年   432篇
  1967年   377篇
  1966年   365篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
781.
782.
An experiment was conducted to explore the quantitative relationship between "goodness" and the amount of symmetry in visual designs. Subjects arranged items in one, two, and three dimensions in an aesthetically pleasing manner. Each design was analyzed to determine its amount of symmetry, and the percent of subjects who created designs having each possible degree of asymmetry was calculated. Perfect symmetry was the most common condition for all three dimensions. Moreover, the goodness of patterns was inversely related to the quantitative degree of asymmetry.  相似文献   
783.
784.
785.
786.
This study investigated the differences in vocational attitude maturity and self-concept among Holland's six vocational categories. Data regarding self-concept, vocational attitude maturity, and vocational preference were gathered from 846 students randomly selected from grades 8–12 in an urban school system. An analysis of variance supported the research hypotheses: (1) There were significant differences in vocational attitude maturity among students in the six vocational categories; (2) there were significant differences in self-concept among students in the six vocational categories; (3) there was a significant relationship between vocational attitude maturity and self-concept among students in specific vocational categories.  相似文献   
787.
This study investigated the duration effect of flooding ‘in vivo’ and ‘in fantasy’ in twelve obsessive-compulsive patients treated in a balanced Latin square design. Clinical assessments regarding twenty one clinical variables were carried out before and after each treatment condition. Long practice sessions proved significantly superior to other treatment conditions. Short and long sessions ‘in fantasy’ did not diner significantly. Long fantasy sessions appear to have potentiating effects on in vivo practice sessions. The order effect and the intercorrelation of the variables prior to treatment and to the outcome, are also presented. Some prognostic factors and the follow-up findings are discussed.  相似文献   
788.
Data representing high, medium, and low response rates in constant and nonconstant patterns were generated by electromechanical equipment to determine whether the same data collected by time-sampling, interval recording, and frequency recording would be represented similarly by each method. Results indicated: (1) that time-sampling provided an extremely inaccurate estimate of responding, and (2) that interval recording accurately represented responding of low and medium rates, but grossly underestimated high-rate responding.  相似文献   
789.
110 blind children in Grades 2 through 12 were matched with sighted controls for age, sex, and verbal reasoning ability. Spatial reasoning was compared with nonspatial reasoning ability for the two groups. At each age level, blind children were inferior to sighted children on spatial reasoning, although the two groups did not differ on nonspatial reasoning. Data further support the likelihood that certain interactions with the perceptual environment may be crucial to specific aspects of cognitive functioning in humans.  相似文献   
790.
Rehearsal, backward counting, and production of alpha brain-waves were used as interpolated tasks in a Brown-Peterson paradigm to determine their effect upon verbal retention. A within-subjects design was used in which trained subjects were told on a given trial either to produce alpha rhythm, mentally rehearse, or count backward following presentation of a CCC trigram. Results for the backward-counting condition duplicate, for the retention intervals used, the shape of the classic Peterson and Peterson forgetting curve but indicate little loss of memory in either the rehearsal or alpha conditions. No siginificant difference was found between the alpha production and rehearsal conditions.  相似文献   
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