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   38522篇
  免费   847篇
  国内免费   1篇
管理学   5453篇
民族学   231篇
人才学   1篇
人口学   4839篇
丛书文集   129篇
教育普及   2篇
理论方法论   3073篇
现状及发展   1篇
综合类   565篇
社会学   18399篇
统计学   6677篇
  2023年   193篇
  2021年   176篇
  2020年   481篇
  2019年   696篇
  2018年   2316篇
  2017年   2589篇
  2016年   1780篇
  2015年   612篇
  2014年   821篇
  2013年   5226篇
  2012年   1328篇
  2011年   1947篇
  2010年   1659篇
  2009年   1330篇
  2008年   1491篇
  2007年   1617篇
  2006年   726篇
  2005年   836篇
  2004年   858篇
  2003年   728篇
  2002年   662篇
  2001年   718篇
  2000年   666篇
  1999年   627篇
  1998年   467篇
  1997年   411篇
  1996年   449篇
  1995年   431篇
  1994年   358篇
  1993年   390篇
  1992年   431篇
  1991年   421篇
  1990年   426篇
  1989年   403篇
  1988年   388篇
  1987年   320篇
  1986年   361篇
  1985年   393篇
  1984年   357篇
  1983年   333篇
  1982年   265篇
  1981年   221篇
  1980年   247篇
  1979年   296篇
  1978年   212篇
  1977年   197篇
  1976年   171篇
  1975年   165篇
  1974年   162篇
  1973年   134篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
191.
Governments around the world combat inequality by means of group-specific redistribution. Some pursue redistribution that benefits groups, but also wish to avoid accentuating or even recognizing group distinctions. This poses a dilemma that they try to resolve by adjusting the category system used to target redistribution. There are three types of adjustment: accommodation (the multicultural approach), denial (the ideal-typical liberal solution), and replacement (a compromise). In replacement the targets of redistributive policies are constructed to avoid accentuation or recognition of inconvenient group distinctions, but still allow redistribution that benefits these groups. Replacement is increasingly in demand around the world because the disadvantages of multiculturalism are becoming apparent while denial is hard to sustain in the face of group inequality. The actual effect of replacement is little researched and less understood, however. Does it resolve the dilemma of recognition? Two examples–India and Nigeria–where replacement has been tried ever since the 1950s cast doubt on its viability.  相似文献   
192.
Projecting losses associated with hurricanes is a complex and difficult undertaking that is wrought with uncertainties. Hurricane Charley, which struck southwest Florida on August 13, 2004, illustrates the uncertainty of forecasting damages from these storms. Due to shifts in the track and the rapid intensification of the storm, real-time estimates grew from 2 to 3 billion dollars in losses late on August 12 to a peak of 50 billion dollars for a brief time as the storm appeared to be headed for the Tampa Bay area. The storm hit the resort areas of Charlotte Harbor near Punta Gorda and then went on to Orlando in the central part of the state, with early poststorm estimates converging on a damage estimate in the 28 to 31 billion dollars range. Comparable damage to central Florida had not been seen since Hurricane Donna in 1960. The Florida Commission on Hurricane Loss Projection Methodology (FCHLPM) has recognized the role of computer models in projecting losses from hurricanes. The FCHLPM established a professional team to perform onsite (confidential) audits of computer models developed by several different companies in the United States that seek to have their models approved for use in insurance rate filings in Florida. The team's members represent the fields of actuarial science, computer science, meteorology, statistics, and wind and structural engineering. An important part of the auditing process requires uncertainty and sensitivity analyses to be performed with the applicant's proprietary model. To influence future such analyses, an uncertainty and sensitivity analysis has been completed for loss projections arising from use of a Holland B parameter hurricane wind field model. Uncertainty analysis quantifies the expected percentage reduction in the uncertainty of wind speed and loss that is attributable to each of the input variables.  相似文献   
193.
The visible and political gay community has been characterized as an increasingly middle-class, white institution. It is hypothesized that this middle-class nature requires economic and psychosocial resources that are not available to the working class and, thus, may limit the expression of sexual orientation for the working class. An analysis of data from the multicity Urban Men's Health Study supports this hypothesis. Nine of 14 hypothesized effects are statistically significant and indicate that working-class men who are homosexually active are less likely to describe themselves as gay, are more likely to have heterosexual experience, and are less likely to be involved in the gay community. Thus, it is important to incorporate class differences when addressing the social and the political dynamics of sexual orientation.  相似文献   
194.
In this paper we develop a study on several types of parallel genetic algorithms (PGAs). Our motivation is to bring some uniformity to the proposal, comparison, and knowledge exchange among the traditionally opposite kinds of serial and parallel GAs. We comparatively analyze the properties of steady-state, generational, and cellular genetic algorithms. Afterwards, this study is extended to consider a distributed model consisting in a ring of GA islands. The analyzed features are the time complexity, selection pressure, schema processing rates, efficacy in finding an optimum, efficiency, speedup, and resistance to scalability. Besides that, we briefly discuss how the migration policy affects the search. Also, some of the search properties of cellular GAs are investigated. The selected benchmark is a representative subset of problems containing real world difficulties. We often conclude that parallel GAs are numerically better and faster than equivalent sequential GAs. Our aim is to shed some light on the advantages and drawbacks of various sequential and parallel GAs to help researchers using them in the very diverse application fields of the evolutionary computation.  相似文献   
195.
196.
Summary.  We define residuals for point process models fitted to spatial point pattern data, and we propose diagnostic plots based on them. The residuals apply to any point process model that has a conditional intensity; the model may exhibit spatial heterogeneity, interpoint interaction and dependence on spatial covariates. Some existing ad hoc methods for model checking (quadrat counts, scan statistic, kernel smoothed intensity and Berman's diagnostic) are recovered as special cases. Diagnostic tools are developed systematically, by using an analogy between our spatial residuals and the usual residuals for (non-spatial) generalized linear models. The conditional intensity λ plays the role of the mean response. This makes it possible to adapt existing knowledge about model validation for generalized linear models to the spatial point process context, giving recommendations for diagnostic plots. A plot of smoothed residuals against spatial location, or against a spatial covariate, is effective in diagnosing spatial trend or co-variate effects. Q – Q -plots of the residuals are effective in diagnosing interpoint interaction.  相似文献   
197.
The extent to which 4‐month attentional regulation during an infant‐mother still‐face situation and 12‐month attachment security during the Strange Situation predicted rates of compliance and noncompliance during a cleanup task at 36 months was examined longitudinally in 70 infant‐mother dyads. Hierarchical multiple regression analyses indicated that infants who showed more attentional regulation during the still‐face situation with mothers later showed a higher rate of committed compliance and a lower rate of situational compliance during cleanup with mothers. Furthermore, lower levels of attentional regulation were later associated with higher rates of assertive behavior, but only for infants in an insecure attachment relationship.  相似文献   
198.
THE ANSWERING MACHINE POSES MANY QUESTIONS FOR TELEPHONE SURVEY RESEARCHERS   总被引:1,自引:0,他引:1  
The proliferation of the telephone answering machine raisesa number of questions about the continued efficiency of thetelephone as a data-gathering mechanism. The most critical ofthese is what effect the use of these machines might have onestablishing contact with potential respondents. If individualsroutinely use these machines to screen calls, then their accessibilityto telephone survey researchers will be restricted. A secondquestion is the degree to which respondents who own answeringmachines and are reachable are likely to participate in a survey.A third question is the extent to which the incidence of theanswering machine as a response disposition might vary by thetime of calling and the respondent's place of residence. Thefindings of this study, based on a nationwide survey, pointto a significant proportion of answering machine owners beingreachable and willing to participate. Furthermore, the answeringmachine appears to be in use more on weekends than on weekdayevenings and in more urbanized areas than in areas with fewerinhabitants.  相似文献   
199.
As a result in part of the way non-profit institutions are defined and treated in the United Nations System of National Accounts (SNA), little is known about the size, scope, financial base and role of this set of institutions at the international level, even though their importance is increasingly being recognised throughout the world. To remedy this significant lack of systematic information on non-profit institutions cross-nationally, the Johns Hopkins Comparative Nonprofit Sector Project has undertaken a major analysis of the economic role of this sector in twelve countries throughout the world, utilising a more meaningful definition of the sector and an approach that is otherwise consistent with the overall thrust of the SNA system. This paper outlines the basis of the more inclusive definition of the non-profit sector embodied in this project, the classification system formulated to structure data-gathering on this more broadly-defined sector and the data assembly strategy developed to build up key estimates of the scale, structure and revenue sources of the non-profit sector in the project countries. The article concludes with a recommendation to incorporate a similar approach to the assembly of data on the non-profit sector into the ongoing SNA system on a regular basis.Professor Lester Salamon is Director of the Institute for Policy Studies and Director of the Comparative Nonprofit Sector Project at the Johns Hopkins University, Baltimore, Maryland, 21218.Helmut Anheier is Research Scientist at the Institute for Policy Studies at the Johns Hopkins University and Assistant Professor of Sociology at Rutgers University, New Brunswick, New Jersey, 08903. He is co-editor ofVoluntas.  相似文献   
200.
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