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   27501篇
  免费   1679篇
  国内免费   44篇
  29224篇
  2018年   298篇
  2017年   338篇
  2016年   386篇
  2015年   301篇
  2014年   331篇
  2013年   1936篇
  2012年   650篇
  2011年   683篇
  2010年   495篇
  2009年   577篇
  2008年   662篇
  2007年   621篇
  2006年   518篇
  2005年   529篇
  2004年   516篇
  2003年   520篇
  2002年   505篇
  2001年   786篇
  2000年   714篇
  1999年   542篇
  1998年   315篇
  1997年   273篇
  1996年   293篇
  1995年   272篇
  1992年   549篇
  1991年   531篇
  1990年   525篇
  1989年   521篇
  1988年   462篇
  1987年   464篇
  1986年   481篇
  1985年   507篇
  1984年   440篇
  1983年   384篇
  1982年   308篇
  1981年   336篇
  1979年   462篇
  1978年   327篇
  1977年   298篇
  1976年   292篇
  1975年   417篇
  1974年   475篇
  1973年   512篇
  1972年   452篇
  1971年   443篇
  1970年   401篇
  1969年   427篇
  1968年   543篇
  1967年   507篇
  1966年   494篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
A cost-benefit analysis of demand for food.   总被引:20,自引:17,他引:3       下载免费PDF全文
Laboratory studies of consumer demand theory require assumptions regarding the definition of price in the absence of a medium of exchange (money). In this study we test the proposition that the fundamental dimension of price is a cost-benefit ratio expressed as the effort expended per unit of food value consumed. Using rats as subjects, we tested the generality of this "unit price" concept by varying four dimensions of price: fixed-ratio schedule, number of food pellets per fixed-ratio completion, probability of reinforcement, and response lever weight or effort. Two levels of the last three factors were combined in a 2 x 2 x 2 design giving eight groups. Each group was studied under a series of six FR schedules. Using the nominal values of all factors to determine unit price, we found that grams of food consumed plotted as a function of unit price followed a single demand curve. Similarly, total work output (responses x effort) conformed to a single function when plotted in terms of unit price. These observations provided a template for interpreting the effects of biological factors, such as brain lesions or drugs, that might alter the cost-benefit ratio.  相似文献   
82.
In a study of air traffic controllers, religious differences are found in the way Type A behavior is associated with several health status indicators. Associations between the Jenkins Activity Survey (JAS) and physical illness incidence, health-promotive behavior, diastolic and systolic blood pressure, subjective distress and impulse control problems, and alcohol consumption are examined by religious attendance, religious affiliation, and change in affiliation. Findings confirm that Type A does not vary significantly by religion. However, there are several significant findings between Type A and various health indicators. Type A is associated with illness incidence, overall and more strongly in several religion, subgroups. Type A and alcohol consumption are related positively in Protestants and converts, and negatively in churchgoing Catholics. Type A is related to impulse control problems in churchgoing Protestants and to subjective distress in churchgoing Catholics. Finally, in individuals with weak or no religious ties, Type A is associated with lower blood pressure. This last finding suggests that in some people (for example, the irreligious or unchurched), the coronary-prone behavior pattern may have cardiovascular effects which are salutary in at least one respect.The authors wish to thank Dr. Kyriakos S. Markides and Laura A. Ray for their assistance with this study. Address requests for reprints to Dr. Levin at the Institute of Gerontology, 300 North Ingalls, Ann Arbor, MI 48109.  相似文献   
83.
84.
This essay reports a program of research as the occupational and personal stress experienced by contemporary American clergy. Three studies are reported. In the first survey a group of largely Roman Catholic religious reported less stress than the general population. In a replication of this investigation on over 510 Protestant clergy this impression of less experienced stress and greater personal resources was confirmed. In the most recent study of clergy in Southern California, a mixed picture was observed. Although the impression of less overall stress was confirmed, great differences in layclery role expectations were observed.He is the coauthorof Clergy Malpractice: How to Care Carefully (Westminster Press, 1986) and is engaged in a variety of ministerial studies.Paper presented at the meeting of the International Council of Psychologists, Mexico City, September, 1984.  相似文献   
85.
86.
The Rosenberg Self-esteem Scale was administered to 550 14- and 16-yr.-old (+/- 6 mo.) girls. Self-esteem scores were categorized by weight and weight by height. Scores on the Quetelet Index for obesity were correlated with self-esteem scores. Mean self-esteem of the low- and middle-weight by height group was significantly higher than the mean of the high-weight by height group. In analyzing weight alone, the self-esteem of the middle-weight group was significantly higher than the self-esteem of the high-weight group. The correlation of the obesity index and self-esteem indicated that as weight increased self-esteem decreased.  相似文献   
87.
88.
89.
90.
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