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   92197篇
  免费   2026篇
  国内免费   4篇
管理学   12606篇
民族学   554篇
人才学   26篇
人口学   6991篇
丛书文集   527篇
理论方法论   9668篇
综合类   2150篇
社会学   42695篇
统计学   19010篇
  2023年   528篇
  2021年   580篇
  2020年   1557篇
  2019年   2281篇
  2018年   2128篇
  2017年   3222篇
  2016年   2431篇
  2015年   2109篇
  2014年   2685篇
  2013年   19165篇
  2012年   2411篇
  2011年   2239篇
  2010年   2023篇
  2009年   2226篇
  2008年   2077篇
  2007年   1906篇
  2006年   2151篇
  2005年   2319篇
  2004年   2220篇
  2003年   1904篇
  2002年   2036篇
  2001年   1992篇
  2000年   1782篇
  1999年   1684篇
  1998年   1515篇
  1997年   1362篇
  1996年   1307篇
  1995年   1316篇
  1994年   1295篇
  1993年   1290篇
  1992年   1261篇
  1991年   1203篇
  1990年   1171篇
  1989年   1040篇
  1988年   1087篇
  1987年   979篇
  1986年   871篇
  1985年   1054篇
  1984年   1108篇
  1983年   1003篇
  1982年   932篇
  1981年   856篇
  1980年   820篇
  1979年   859篇
  1978年   770篇
  1977年   692篇
  1976年   656篇
  1975年   628篇
  1974年   524篇
  1973年   427篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
The use of time for child care and housework among Swedish families is investigated. We allow the effect of children on child care and housework to vary by age of the child and also by whether the child is cared for outside the home or not. Our estimates allow us to compute the total cost of children in the form of the cost of time, and the cost of goods, services and housing.The result shows that time used for child care decreases sharply with the age of the child but this is not the case for time used for other housework. Considerable economies of scale is found to prevail for time used for child care. Child care outside the home reduces time use for other housework but the effect on time used for child care is quite small. For the average family time use cost make up more than half of total child cost. Our estimates indicate that decreased time use cost for children caused by care outside the home are not very different from a typical parental fee for public day care.This research was supported by a grant from the Swedish Council of Social Research (SFR). We thank Lennart Flood for useful comments on an earlier version.  相似文献   
992.
The authors outline demographic trends in Eastern Europe and Russia since 1970. Aspects considered include population size, birth rate and number of births, marriage and divorce, death rate, infant mortality, natural increase, sex ratio, and life expectancy.  相似文献   
993.
Contemporary immigration to the United States and the formation of new ethnic groups are the complex and unintended social consequences of the expansion of the nation to its post-World War II position of global hegemony. Immigrant communities in the United States today are related to a history of American military, political, economic, and cultural involvement and intervention in the sending countries, especially in Asia and the Caribbean Basin, and to the linkages that are formed in the process that open a variety of legal and illegal migration pathways. The 19.8 million foreign-born persons counted in the 1990 U.S. census formed the largest immigrant population in the world, though in relative terms, only 7.9% of the U.S. population was foreign-born, a lower proportion than earlier in this century. Today's immigrants are extraordinarily diverse, a reflection of polar-opposite types of migrations embedded in very different historical and structural contexts. Also, unlike the expanding economy that absorbed earlier flows from Europe, since the 1970s new immigrants have entered an hourglass economy with reduced opportunities for social mobility, particularly among the less educated, and new waves of refugees have entered a welfare state with expanded opportunities for public assistance. This paper seeks to make sense of the new diversity. A typology of contemporary immigrants is presented, and their patterns of settlement, their distinctive social and economic characteristics compared to major native-born racial-ethnic groups, and their different modes of incorporation in—and consequences for—American society are considered.  相似文献   
994.
The benefits of providing a separate accounting for non-profit organisations in the financial accounts of the United States are discussed. At present, national economic accounts in the US include non-profit organisations with individuals in the household sector; separate information on the financial activity of non-profit institutions until now has not been available. In this paper, aggregate statistics from federal government tax-exempt filings for non-profit institutions are put into a US flow-of-funds framework. The data for the 1982–1988 period indicate that non-profit institutions accounted for a significant and growing proportion of assets of the household sector in the United States. Their liabilities were also a surprisingly large share of the household sector total. Moreover, funds supplied by the non-profit sector for investment were in some years comparable to funds made available by several important groups of non-depository financial intermediaries. Separate accounting for non-profit organisations within national economic accounts would be likely to reveal an important channel for investment financing in the United States and would significantly improve our ability to measure and analyse the financial activity of individuals by allowing for a purer household sector.The analysis and conclusions set forth are those of the authors and do not necessarily indicate concurrence by Salomon Brothers, the Board of Governors, Federal Reserve Banks or other members of their staffs.  相似文献   
995.
The success of the third sector depends on public confidence, and that confidence rests, in part, on holding managers, directors, and officers of nonprofits responsible for their conduct. This accountability can be accomplished by clearly defining the roles of these individuals and the stands that they are to uphold, and by providing channels for all interested to challenge uncontrolled activities. Though interest in this goal is unanimous, a debate exists over how to ensure oversight and accountability.  相似文献   
996.
Evolution strategies (ESs) are a special class of probabilistic, direct, global optimization methods. They are similar to genetic algorithms but work in continuous spaces and have the additional capability of self-adapting their major strategy parameters. This paper presents the most important features of ESs, namely their self-adaptation, as well as their robustness and potential for parallelization which they share with other evolutionary algorithms.Besides the early (1 + 1)-ES and its underlying theoretical results, the modern ( + )-ES and (, )-ES are presented with special emphasis on the self-adaptation of strategy parameters, a mechanism which enables the algorithm to evolve not only the object variables but also the characteristics of the probability distributions of normally distributed mutations. The self-adaptation property of the algorithm is also illustrated by an experimental example.The robustness of ESs is demonstrated for noisy fitness evaluations and by its application to discrete optimization problems, namely the travelling salesman problem (TSP).Finally, the paper concludes by summarizing existing work and general possibilities regarding the parallelization of evolution strategies and evolutionary algorithms in general.  相似文献   
997.
Common binary regression models such as logistic or probit regression have been extended to include parametric link transformation families. These binary regression models with parametric link are designed to avoid possible link misspecification and improve fit in some data sets. One and two parameter link families have been proposed in the literature (for a review see Stukel (1988)). However in real data examples published so far only one parameter link families have found to improve the fit significantly. This paper introduces a two parameter link family involving the modification of both tails of the link. An analysis based on computationally tractable Bayesian inference involving Monte Carlo sampling algorithms is presented extending earlier work of Czado (1992, 1993b). Finally, the usefulness of the two tailed link modification will be demonstrated in an example where single tail modification can be significantly improved upon by using a two tailed modification.  相似文献   
998.
This paper considers the application of Stein-type estimation procedure for the coefficients in a linear regression model when data are available from replicated experiment. Two families of estimators characterized by a single scalar are proposed and their large sample asymptotic properties are derived. These are utilized for comparing the performances of the two estimators along with the conventional estimator and conditions for the superiority of one estimator over the other are deduced.  相似文献   
999.
Outdoor structured activities, such as Ropes Challenge Courses, are typically utilized as interventions for youth coming from urban settings. Evaluation of such programs is scanty at best. In this instance, the course experience is used as a prevention tool for high risk youth in a remote, rural setting of high unemployment, alcohol problems, and low income. The authors discuss the effectiveness of this approach, and the intended and unintended consequences for the rural community at large. The evaluation design relies on extensive qualitative methodology as well as quantitative methods to capture the unique nature of this rural project.  相似文献   
1000.
Because the item, "How concerned are you about...?" asks respondentsto indicate their level of concern about an issue, some respondentsmay sense it assumes they are concerned or should be concernedabout the issue. Using a filter question to first determineif people are concerned about the issue before asking for theirdegree of concern may help solve this problem. To test thishypothesis, a split-ballot experiment was embedded in a nationalrandom digit dialing telephone survey on food-related issues.For the four items included in the experiment, the group receivingthe filter versions of the questions gave roughly double thepercentages of "not concerned" responses as the group receivingstandard items, and the filter group also gave fewer responsesat the upper end of the response scale.  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