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   12880篇
  免费   300篇
管理学   1684篇
民族学   52篇
人才学   1篇
人口学   1121篇
丛书文集   78篇
教育普及   2篇
理论方法论   1195篇
综合类   337篇
社会学   6486篇
统计学   2224篇
  2021年   67篇
  2020年   195篇
  2019年   226篇
  2018年   252篇
  2017年   373篇
  2016年   287篇
  2015年   242篇
  2014年   260篇
  2013年   2096篇
  2012年   403篇
  2011年   326篇
  2010年   218篇
  2009年   244篇
  2008年   268篇
  2007年   296篇
  2006年   224篇
  2005年   360篇
  2004年   308篇
  2003年   264篇
  2002年   275篇
  2001年   318篇
  2000年   299篇
  1999年   315篇
  1998年   210篇
  1997年   205篇
  1996年   217篇
  1995年   190篇
  1994年   205篇
  1993年   178篇
  1992年   237篇
  1991年   235篇
  1990年   212篇
  1989年   221篇
  1988年   198篇
  1987年   186篇
  1986年   191篇
  1985年   175篇
  1984年   207篇
  1983年   202篇
  1982年   165篇
  1981年   137篇
  1980年   139篇
  1979年   166篇
  1978年   136篇
  1977年   119篇
  1976年   103篇
  1975年   101篇
  1974年   95篇
  1973年   93篇
  1971年   64篇
排序方式: 共有10000条查询结果,搜索用时 718 毫秒
121.
122.
123.
124.
This paper describes specific transference and counter-transference issues that commonly emerge in therapeutic work with adolescents and parents who are in the midst of family transitions such as divorce and remarriage. Psychoanalytic understanding and definitions of transference and countertransference are applied to short-term family-centered cases in which the parent-adolescent relationship is at particular risk. Case vignettes are presented in order to illustrate how transference and countertransference may guide or interfere with clinical interventions that are especially indicated with adolescents whose family structure has changed. Such interventions as well as the use of consultation are briefly described.At the time this paper was prepared, Ms. Springer was Associate Director and a senior clinician at the Center for the Family in Transition in Corte Madera, California. Funds for the research and clinical work that provided the basis for this paper were supplied by grants from the San Francisco Foudation. An earlier version of this paper was presented at the 66th Annual Meeting of the American Orthopsychiatry Association, New York City, March 31–April 4, 1989.  相似文献   
125.
针对平衡倒立摆这一非线性控制问题,设计了神经元控制器和控制装置,编制了实时控制程序.控制装置运行良好,成功地平衡了倒立摆.实时控制实验显示,当倒立摆的参数变化时,神经元控制器比一般的控制器具有强得多的自适应能力.  相似文献   
126.
This report summarizes the proceedings of a conference on quantitative methods for assessing the risks of developmental toxicants. The conference was planned by a subcommittee of the National Research Council's Committee on Risk Assessment Methodology 4 in conjunction with staff from several federal agencies, including the U.S. Environmental Protection Agency, U.S. Food and Drug Administration, U.S. Consumer Products Safety Commission, and Health and Welfare Canada. Issues discussed at the workshop included computerized techniques for hazard identification, use of human and animal data for defining risks in a clinical setting, relationships between end points in developmental toxicity testing, reference dose calculations for developmental toxicology, analysis of quantitative dose-response data, mechanisms of developmental toxicity, physiologically based pharmacokinetic models, and structure-activity relationships. Although a formal consensus was not sought, many participants favored the evolution of quantitative techniques for developmental toxicology risk assessment, including the replacement of lowest observed adverse effect levels (LOAELs) and no observed adverse effect levels (NOAELs) with the benchmark dose methodology.  相似文献   
127.
The skin is a route of exposure that needs to be considered when conducting a risk assessment. It is necessary to identify the potential for dermal penetration by a chemical as well as to determine the overall importance of the dermal route of exposure as compared with inhalation or oral routes of exposure. The physical state of the chemical, vapor or liquid, the concentration, neat or dilute, and the vehicle, lipid or aqueous, is also important. Dermal risk is related to the product of the amounts of penetration and toxicity. Toxicity involves local effects on the skin itself and the potential for systemic effects. Dermal penetration is described in large part by the permeability constant. When permeability constants are not known, partition coefficients can be used to estimate a chemical's potential to permeate the skin. With these concepts in mind, a tiered approach is proposed for dermal risk assessment. A key first step is the determination of a skin-to-air or skin-to-medium partition coefficient to estimate a potential for dermal absorption. Building a physiologically-based pharmacokinetic (PBPK) model is another step in the tiered approach and is useful prior to classical in vivo toxicity tests. A PBPK model can be used to determine a permeability constant for a chemical as well as to show the distribution of the chemical systemically. A detailed understanding of species differences in the structure and function of the skin and how they relate to differences in penetration rates is necessary in order to extrapolate animal data from PBPK models to the human. A study is in progress to examine anatomical differences for four species.  相似文献   
128.
Marriage and fertility in the United States have become less firmly entwined as more women bear children without marrying and more couples with children divorce. Today a sizeable number of children are expected to spend a portion of their childhood in one-parent households. Despite the trends in illegitimacy and divorce, the actual effect of out-of-wedlock childbearing on the living arrangements of children has not been fully explicated. Using the National Survey of Family Growth Cycle III, this paper estimates the probability that children aged 0–13 in 1982 are living in two-parent households, controlling for their mothers' marital statuses at their births. We find that marital status at birth is an important predictor of household structure at later ages for both white and black populations; however, the childhood environment is actually quite elastic as women marry, divorce, remarry, and redivorce.  相似文献   
129.
RURAL POVERTY, URBAN POVERTY, AND PSYCHOLOGICAL WELL-BEING   总被引:1,自引:0,他引:1  
Data from the National Survey of Families and Households are used to compare the psychological well-being of the rural and urban poor. Overall, the urban poor are higher in perceived health than the rural poor, although no differences are apparent in happiness or depression. Significant interactions are present between rural/urban poverty and sex, race, and family status. The psychological well-being of poor African Americans is higher in rural than urban areas, whereas the well-being of poor whites is higher in urban than rural areas. This trend is especially pronounced for depression among males. In addition, single men without children have especially high depression scores in rural areas, whereas married women without children have especially low depression scores in urban areas. The results are interpreted in terms of the environmental quality of inner-city neighborhoods and attitudes toward poverty in urban and rural communities.  相似文献   
130.
This article examines the relationship between donations to the American Red Cross and the profits, sales, costs, and prices of health and safety classes offered by local chapters. Two important questions are examined: Do profits from sales of services “crowd out” donations to local chapters of the American Red Cross? Do managers respond to changes in donations by changing prices, output, or costs of saleable services? The results suggest that nonprofit managers should pay close attention to the potential impact on donations of any change in the prices charged for saleable goods and services, and that profits, costs, and prices of services are influenced by donations.  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