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   96518篇
  免费   3020篇
  国内免费   5篇
管理学   13255篇
民族学   563篇
人才学   26篇
人口学   7795篇
丛书文集   555篇
教育普及   2篇
理论方法论   9910篇
现状及发展   1篇
综合类   2265篇
社会学   45793篇
统计学   19378篇
  2023年   517篇
  2021年   586篇
  2020年   1547篇
  2019年   2256篇
  2018年   2231篇
  2017年   3312篇
  2016年   2536篇
  2015年   2119篇
  2014年   2682篇
  2013年   19136篇
  2012年   2663篇
  2011年   2483篇
  2010年   2157篇
  2009年   2302篇
  2008年   2224篇
  2007年   2060篇
  2006年   2247篇
  2005年   2458篇
  2004年   2299篇
  2003年   2026篇
  2002年   2147篇
  2001年   2202篇
  2000年   1992篇
  1999年   1846篇
  1998年   1598篇
  1997年   1475篇
  1996年   1413篇
  1995年   1432篇
  1994年   1400篇
  1993年   1387篇
  1992年   1403篇
  1991年   1331篇
  1990年   1318篇
  1989年   1163篇
  1988年   1250篇
  1987年   1119篇
  1986年   1026篇
  1985年   1189篇
  1984年   1239篇
  1983年   1123篇
  1982年   1023篇
  1981年   924篇
  1980年   869篇
  1979年   970篇
  1978年   843篇
  1977年   738篇
  1976年   705篇
  1975年   684篇
  1974年   573篇
  1973年   492篇
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
951.
As the number of individuals and families impacted by AIDS continue to multiply, family therapists will increasingly be asked to become engaged in the challenge of caring for those affected. To date, little has been written in family therpy journals regarding the response of family therapists to this crisis. This paper represents an initial attempt to examine the atitudes of clinical members of the American Association for Marriage and Family Therapy toward AIDS and persons with AIDS. Included in the study are data regarding the therapists' contact with persons with AIDS, gays, and lesbians, and the impact of such contact on attitudes. Implications for future research, training, and treatment of those affected by AIDS are also provided.  相似文献   
952.
953.
This is an analysis of the social context of normal police lies. We define lies as speech acts which the speaker knows are misleading or false, are intended to deceive, and where evidence to the contrary is known to the observer. Lies are relative to a moral context, and what an audience will accept. Lies include excuses, which deny full responsibility for an act, but acknowledge its immorality, and justifications, which accept responsibility but deny blame-worthiness. Police learn to lie and to carefully distinguish normal (or acceptable) lies from unacceptable lies, suggesting that lies are a part of a negotiated occupational order. We show how and why some types of lies are rewarded by police using ethnographic data from an 18 month field study of a large urban force. Lies can be of little issue, or become troublesome. We report and analyze two kinds of troublesome lies: case lies, recognized stories an officer utilizes in a courtroom or on paper to facilitate the conviction of a suspect, and cover stories, lies an officer tells in court, to supervisors, and on the job with the aim of providing a verbal shield or mitigation in the event of discipline. Both excuses and justifications are woven together in these vignettes. An example of a refusal to lie is used to illustrate some of the limits on lying as well organizational factors in lying. Some implications for official lying are also noted.  相似文献   
954.
955.
The problem of determining the number of multi-type protection devices and their locations on electrical supply tree networks with subtree dependency is investigated. The aim is to reduce the amount of inconvenience caused to customers that are affected by any given fault on the networks. An appropriate implementation of tabu search is proposed. We exploit a variable neighborhood and a soft aspiration level, and we embed a data structure and reduction tests into the search to speed up the process. Computational tests are performed on randomly generated electrical tree networks varying in size and branch complexity with encouraging results.  相似文献   
956.
Since children, particularly daughters, are among the most important sources of help and support for older Americans, it has been suggested that women's increasing employment will affect filial relations. Empirical evidence on this issue is inconsistent, in part due to the use of nonprobability samples. Few studies have measured effects for men. We attempt to broaden the scope of this question beyond help to the frail elderly by asking whether employment affects filial relations in general. We examine effects of hours employed on telephone contact, visiting, feelings of closeness, filial attitudes, and assistance to biological parents, for an area probability sample of men and women over 40. There are no effects of employment for men or women on contact, closeness, or assistance. For the vast majority of this population sample, contact and assistance involve few hours per week, and thus do not seem to conflict with employment.  相似文献   
957.
958.
959.
960.
Tree health is a critical parameter for evaluating urban ecosystem health and sustainability. Traditionally, this parameter has been derived from field surveys. We used multispectral remote sensing data and GIS techniques to determine tree health at the University of California, Davis. The study area (363 ha) contained 8,962 trees of 215 species. Tree health conditions were mapped for each physiognomic type at two scales: pixel and whole tree. At the pixel scale, each tree pixel within the tree crown was classified as either healthy or unhealthy based on vegetation index values. At the whole tree scale, raster based statistical analysis was used to calculate tree health index which is the ratio of healthy pixels to entire tree pixels within the tree crown. The tree was classified as healthy if the index was greater than 70%. Accuracy was checked against a random sample of 1,186 trees. At the whole tree level, 86% of campus trees were classified as healthy with 88% mapping accuracy. At the pixel level, 86% of the campus tree cover was classified as healthy. This tree health evaluation approach allows managers to identify the location of unhealthy trees for further diagnosis and treatment. It can be used to track the spread of disease and monitor seasonal or annual changes in tree health. Also, it provides tree health information that is fundamental to modeling and analysis of the environmental, social, and economic services produced by urban forests.  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