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   13080篇
  免费   348篇
管理学   1691篇
民族学   55篇
人口学   1043篇
丛书文集   69篇
教育普及   3篇
理论方法论   1210篇
综合类   131篇
社会学   6933篇
统计学   2293篇
  2023年   72篇
  2021年   70篇
  2020年   171篇
  2019年   263篇
  2018年   279篇
  2017年   396篇
  2016年   288篇
  2015年   230篇
  2014年   315篇
  2013年   2593篇
  2012年   373篇
  2011年   356篇
  2010年   272篇
  2009年   252篇
  2008年   282篇
  2007年   275篇
  2006年   296篇
  2005年   273篇
  2004年   238篇
  2003年   215篇
  2002年   228篇
  2001年   312篇
  2000年   289篇
  1999年   307篇
  1998年   201篇
  1997年   184篇
  1996年   224篇
  1995年   230篇
  1994年   243篇
  1993年   235篇
  1992年   247篇
  1991年   236篇
  1990年   254篇
  1989年   217篇
  1988年   224篇
  1987年   192篇
  1986年   180篇
  1985年   186篇
  1984年   194篇
  1983年   141篇
  1982年   134篇
  1981年   124篇
  1980年   131篇
  1979年   125篇
  1978年   108篇
  1977年   91篇
  1976年   90篇
  1975年   96篇
  1974年   64篇
  1973年   56篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
This paper reports on a research programme that has investigated the migration experiences of highly skilled professional and business migrants to New Zealand. Over a four‐year period, five separate studies have been conducted on the stages in the process of migration. The paper sets out a model of the stages of the migration process and the data and analysis which it has guided. Of particular interest are the information sources available to potential migrants and employers, the cultural sensitivity of settlement processes and the migrants' subsequent ease of access to the labour market. The paper analyses information flows available to migrants at crucial phases in the migration process based on a stages model of the migration process. The model indicates some of the critical steps, interactions, and decisions in the migration process from the individual's point of view. Crucial information gaps are identified and implications are drawn for actors involved at the different stages.  相似文献   
92.
This article presents the results of a study conducted with 243 Native American students who were part of a multi-ethnic sample of adolescents attending middle school in a large urban center in the Southwest region of the United States. Native adolescents who felt a stronger sense of belonging in their school were found to report a lower lifetime use of alcohol and cigarettes, lower cigarette and marijuana use in the previous month, lower frequency of current use of these substances, fewer substances ever used, and a later age of initiation into drug use than other Native students. Research implications are discussed in relationship to school environment, culturally-grounded prevention curricula, and school social work practice.  相似文献   
93.
This article reports the results of a study that examined the ways in which current and recent TANF recipients assembled or “packaged” their child care arrangements among formal and informal providers. The findings are drawn from in-person, in-depth interviews with current and former welfare recipients. The study found that most of the respondents used multiple providers within the category of informal child care for reasons including availability, the use of a network of social acquaintances as a problem-solving resource, the need to accommodate irregular work hours, and personal trauma that contributed to a distrust of strangers in formal settings. The findings can affect the efficacy of practice with TANF recipients by contributing to social workers’ understanding of the context of decision-making regarding child care.  相似文献   
94.
95.
This paper presents an improved efficiency measurement tool by modifying the existing data envelopment analysis methodology to permit the incorporation of expert knowledge. A previous paper examined the inclusion of such knowledge within the additive model. This information appeared in the form of a binary classification of a subset of the decision making units under study (e.g. good versus poor performers). In the current paper, we extend this logic to the input-oriented radial projection model. We demonstrate that the inclusion of this and other forms of expert judgment can improve the performance of the DEA tool in the sense that the efficiency scores are more in line with expert/management beliefs.  相似文献   
96.
The probability of illness caused by very low doses of pathogens cannot generally be tested due to the numbers of subjects that would be needed, though such assessments of illness dose response are needed to evaluate drinking water standards. A predictive Bayesian dose-response assessment method was proposed previously to assess the unconditional probability of illness from available information and avoid the inconsistencies of confidence-based approaches. However, the method uses knowledge of the conditional dose-response form, and this form is not well established for the illness endpoint. A conditional parametric dose-response function for gastroenteric illness is proposed here based on simple numerical models of self-organized host-pathogen systems and probabilistic arguments. In the models, illnesses terminate when the host evolves by processes of natural selection to a self-organized critical value of wellness. A generalized beta-Poisson illness dose-response form emerges for the population as a whole. Use of this form is demonstrated in a predictive Bayesian dose-response assessment for cryptosporidiosis. Results suggest that a maximum allowable dose of 5.0 x 10(-7) oocysts/exposure (e.g., 2.5 x 10(-7) oocysts/L water) would correspond with the original goals of the U.S. Environmental Protection Agency Surface Water Treatment Rule, considering only primary illnesses resulting from Poisson-distributed pathogen counts. This estimate should be revised to account for non-Poisson distributions of Cryptosporidium parvum in drinking water and total response, considering secondary illness propagation in the population.  相似文献   
97.
Summary.  To investigate the variability in energy output from a network of photovoltaic cells, solar radiation was recorded at 10 sites every 10 min in the Pentland Hills to the south of Edinburgh. We identify spatiotemporal auto-regressive moving average models as the most appropriate to address this problem. Although previously considered computationally prohibitive to work with, we show that by approximating using toroidal space and fitting by matching auto-correlations, calculations can be substantially reduced. We find that a first-order spatiotemporal auto-regressive (STAR(1)) process with a first-order neighbourhood structure and a Matern noise process provide an adequate fit to the data, and we demonstrate its use in simulating realizations of energy output.  相似文献   
98.
The ability to infer parameters of gene regulatory networks is emerging as a key problem in systems biology. The biochemical data are intrinsically stochastic and tend to be observed by means of discrete-time sampling systems, which are often limited in their completeness. In this paper we explore how to make Bayesian inference for the kinetic rate constants of regulatory networks, using the stochastic kinetic Lotka-Volterra system as a model. This simple model describes behaviour typical of many biochemical networks which exhibit auto-regulatory behaviour. Various MCMC algorithms are described and their performance evaluated in several data-poor scenarios. An algorithm based on an approximating process is shown to be particularly efficient.  相似文献   
99.
Summary. Possible health hazards from mobile phones arise from the use of the phones themselves and via the base stations that relay signals. Except for an increase in traffic accidents induced by the use of mobile phones in cars the evidence for a health hazard is at most indirect, but it cannot be entirely dismissed; the phones have not been widely used for sufficiently long for direct epidemiological studies to have high sensitivity for detecting any induced incidence of cancer, for example. The background and evidence are briefly reviewed and the steps taken in the UK to make information widely available described.  相似文献   
100.
The Alchian and Allen theorem predicts that it will be harder to find "good" apples in the State of Washington, a prime apple-growing region, than in, say, New York City, where the addition of shipping charges makes "bad" apples comparatively more expensive. We recast the theorem as a testable proposition by explicitly taking the supply side into account and identifying plausible scenarios in which a fixed cost either has no effect on the relative prices of high and low quality grades of the same good in distant markets or, indeed, causes more of the bad apples to be shipped out.  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