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   389篇
  免费   24篇
管理学   32篇
民族学   4篇
人口学   36篇
丛书文集   2篇
理论方法论   22篇
综合类   27篇
社会学   202篇
统计学   88篇
  2023年   6篇
  2022年   8篇
  2021年   10篇
  2020年   13篇
  2019年   11篇
  2018年   25篇
  2017年   27篇
  2016年   23篇
  2015年   10篇
  2014年   9篇
  2013年   53篇
  2012年   102篇
  2011年   14篇
  2010年   11篇
  2009年   4篇
  2008年   5篇
  2007年   8篇
  2006年   6篇
  2005年   5篇
  2004年   6篇
  2003年   5篇
  2002年   14篇
  2001年   7篇
  2000年   7篇
  1999年   2篇
  1998年   1篇
  1997年   5篇
  1996年   2篇
  1992年   2篇
  1991年   5篇
  1990年   1篇
  1987年   2篇
  1983年   1篇
  1980年   1篇
  1975年   2篇
排序方式: 共有413条查询结果,搜索用时 31 毫秒
401.
A peek through the doors of New York City's Emergency Assistance Unit (EAU), the entryway into the City's family shelter system, presents a shocking snapshot of life for the poorest of America's welfare families: the homeless. Burgeoning with young single mothers and children sitting on floors and sleeping in chairs as they wait for someone to send them on to temporary shelter, the EAU offers a vivid example of the overburdened institutions of support on which poor families depend daily.  相似文献   
402.
Objective. Our objective is to explain how scientists interpret less‐than‐certain scientific findings to inform policymakers' choices on controversial science policy issues. We focus on two particularly difficult policy cases concerning global climate change and low‐dose radiation protection. Methods. Our method is to analyze data from a unique multination survey of scientists to analyze the ways their views about what is scientifically correct are translated into judgments about appropriate policy. The surveys asked scientists, randomly drawn from U.S. and E.U. subscribers to the journal Science, to indicate the “most likely” relationships between greenhouse gas emissions and average global temperatures and between radiation dose and incidence of cancer in humans. Follow‐up questions asked for their judgments about appropriate policy targets for reductions in greenhouse gas emission and safety standards for radiation exposure. The data permit analysis of the relationships between scientific certainty and policy judgments in these two cases. Results. Our results shed light on when and how scientists reach precautionary policy conclusions, demonstrating that scientists' application of precaution is dependent on context. In the case of radiation protection, greater certainty is associated with less precaution. But with respect climate change, we found the opposite relationship. Conclusions. We conclude with a discussion of the implications for the role of scientists, and scientific advice, in the policy process.  相似文献   
403.
Although Colombia is a major country of emigration, little is known about its citizens' motivations for migration. Social and economic conditions have been studied as determinants of migration, but violence has received less attention. We examine how social networks and violence function to promote emigration from Colombia by linking event‐history data from the Latin American Migration Project to external data on violence and economic conditions. We show that emigration is more likely to be initiated by those with higher education, those with network connections to migrants, and during periods of greater violence and increased police presence. Although violence acts powerfully to determine when people migrate, the geographic distribution of social capital determines where they go. Not surprisingly, migrants go to locations where people in their social networks are currently living or have been earlier.  相似文献   
404.
405.
A lead time that is short, predictable, and reliable is an increasingly important criterion in supplier selection. Although many companies may achieve this through lean implementation, high‐variety manufacturers, for example, small and medium‐sized make‐to‐order companies, have found that lean's planning and control techniques do not apply. This article outlines a planning and control concept known as workload control (WLC) that integrates customer enquiry management, including a due‐date setting rule, with order release control. Simulation is then used to assess its impact on shop performance. Results demonstrate that an integrated WLC concept can reduce the percentage of tardy jobs—so short lead times can be realistically quoted—while also reducing and stabilizing workloads. WLC can level demand and production over time when work is not standardized and it is not possible to synchronize flows on the shop floor. Results are shown to be robust to changes in routing characteristics, the mix of orders with due dates specified by the customer and proposed internally, and the strike rate (or order‐winning probability). Hence, an integrated approach to WLC represents an important step toward achieving lean in make‐to‐order companies.  相似文献   
406.
Journal of Combinatorial Optimization - The Angular Constrained Minimum Spanning Tree Problem ( $$\alpha $$ -MSTP) is defined in terms of a complete undirected graph $$G=(V,E)$$ and an angle...  相似文献   
407.
The modeling and analysis of experiments is an important aspect of statistical work in a wide variety of scientific and technological fields. We introduce and study the odd log-logistic skew-normal model, which can be interpreted as a generalization of the skew-normal distribution. The new distribution can be used effectively in the analysis of experiments data since it accommodates unimodal, bimodal, symmetric, bimodal and right-skewed, and bimodal and left-skewed density function depending on the parameter values. We illustrate the importance of the new model by means of three real data sets in analysis of experiments.  相似文献   
408.
In obstetrics and gynecology, knowledge about how women''s features are associated with childbirth is important. This leads to establishing guidelines and can help managers to describe the dynamics of pregnant women''s hospital stays. Then, time is a variable of great importance and can be described by survival models. An issue that should be considered in the modeling is the inclusion of women for whom the duration of labor cannot be observed due to fetal death, generating a proportion of times equal to zero. Additionally, another proportion of women''s time may be censored due to some intervention. The aim of this paper was to present the Log-Normal zero-inflated cure regression model and to evaluate likelihood-based parameter estimation by a simulation study. In general, the inference procedures showed a better performance for larger samples and low proportions of zero inflation and cure. To exemplify how this model can be an important tool for investigating the course of the childbirth process, we considered the Better Outcomes in Labor Difficulty project dataset and showed that parity and educational level are associated with the main outcomes. We acknowledge the World Health Organization for granting us permission to use the dataset.  相似文献   
409.
410.
This study analyses the expected changes in survivors’ pensions resulting from the permanent rules of the 2019 pension reform in Brazil. Actuarial annuities are used for representative worker profiles. The dispersion in the replacement rate values decreases, except for the highest income level. The rates needed to finance survivors’ pensions decrease relatively more than do the rates for old-age pensions. The internal rates of return significantly decrease. There is a heterogeneous change in the distributive aspects of the pension system. The reform shall affect the adequacy and intragenerational equity of old-age and survivors’ pensions.  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