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   7699篇
  免费   257篇
  国内免费   5篇
  2020年   81篇
  2019年   92篇
  2018年   137篇
  2017年   140篇
  2016年   164篇
  2015年   125篇
  2014年   126篇
  2013年   770篇
  2012年   267篇
  2011年   276篇
  2010年   181篇
  2009年   216篇
  2008年   281篇
  2007年   313篇
  2006年   281篇
  2005年   257篇
  2004年   244篇
  2003年   299篇
  2002年   267篇
  2001年   108篇
  2000年   107篇
  1999年   131篇
  1998年   102篇
  1997年   115篇
  1996年   110篇
  1995年   125篇
  1994年   96篇
  1993年   117篇
  1992年   101篇
  1991年   91篇
  1990年   77篇
  1989年   79篇
  1988年   84篇
  1987年   97篇
  1986年   80篇
  1985年   90篇
  1984年   114篇
  1983年   119篇
  1982年   107篇
  1981年   102篇
  1980年   109篇
  1979年   107篇
  1978年   115篇
  1977年   107篇
  1976年   119篇
  1975年   92篇
  1974年   94篇
  1973年   88篇
  1972年   58篇
  1971年   45篇
排序方式: 共有7961条查询结果,搜索用时 15 毫秒
121.
122.
Pastoral Psychology -  相似文献   
123.
The minimal transformation to orthonormality   总被引:1,自引:0,他引:1  
The solution is presented to the problem of finding that orthonormal matrix closest in the least-square sense to a given matrix of full rank. An application is shown to the problem in multiple regression analysis of determining the importance of each independent variable.  相似文献   
124.
The relationship between the occupational preferences of 147 superior students and their fathers' occupations was traced over the 4-year period that the students attended high schools in Wisconsin. Analysis of the data indicated that both male and female superior students tended to state vocational preferences at the professional level early in high school and to maintain this preference throughout. Their occupational preferences were generally at a higher level than those of their fathers. There was no trend away from general preferences for work at a professional level toward naming of specific occupations within that level. The results suggest that theories of vocational development that imply that stages are passed through during later adolescent periods do not apply to the superior student population of this study.  相似文献   
125.
In 11 male albino rats, lever-pressing responses, maintained under a CRF escape schedule with light as the aversive stimulus, were examined at each of five intensities, viz., 2.5, 18, 105, 190, and 386 ft-C. The function relating reciprocal of latency of the escape response to aversive light intensity passed through a maximum.  相似文献   
126.
Graphic designers and an experimental psychologist worked together to improve the design of two map symbols which are frequently confused: the symbols for cuttings and embankments on topographic maps. The problem was analysed in terms of the function of the symbols and their likely cognitive representations. Tests were developed to evaluate alternative designs, including an intervisibility task which requirred users to visualize the landform from the symbols viewed in the context of a map. Tests were given to schoolchildren and to experienced map users in order to compare the standard symbols with five alternative designs. Children's performance was strongly affected by the symbols they used, but experienced users were much less affected. After some refinement of the symbols a further experiment demonstrated the superiority of a number of alternative designs over the existing symbols on a range of test: scores were almost double on the intervisibility task. The paper makes recommendations to cartographers and argues for greater consideration of the inexperienced map user in the design process.  相似文献   
127.
128.
129.
130.
A new approach is described for the development and structure of perceptual knowledge-based systems. This systematic method for acquiring perceptual knowledge for use in knowledge-based systems and for representing perceptual knowledge within the systems has revealed that two broad classes of perceptual activity can each be characterized by a single logical operator. The number of rules necessary to accomplish particular perceptual tasks can also be estimated.  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