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   294篇
  免费   8篇
管理学   69篇
民族学   1篇
人口学   25篇
丛书文集   3篇
理论方法论   45篇
综合类   4篇
社会学   110篇
统计学   45篇
  2023年   1篇
  2022年   6篇
  2021年   3篇
  2020年   3篇
  2019年   10篇
  2018年   6篇
  2017年   14篇
  2016年   7篇
  2015年   6篇
  2014年   14篇
  2013年   40篇
  2012年   21篇
  2011年   18篇
  2010年   16篇
  2009年   7篇
  2008年   14篇
  2007年   14篇
  2006年   12篇
  2005年   13篇
  2004年   9篇
  2003年   5篇
  2002年   7篇
  2001年   9篇
  2000年   6篇
  1999年   3篇
  1998年   4篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1991年   2篇
  1989年   1篇
  1988年   2篇
  1987年   1篇
  1984年   2篇
  1982年   2篇
  1981年   2篇
  1980年   1篇
  1979年   3篇
  1978年   2篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
  1974年   2篇
  1973年   1篇
  1972年   3篇
  1971年   1篇
  1968年   1篇
排序方式: 共有302条查询结果,搜索用时 15 毫秒
1.
Dental caries in children is now recognized as a preventable disease. The use of fluoride and sealants has produced a major reduction in caries prevalence among school aged children in the United States and other countries. A portion of the child population who are educationally and socioeconomically disadvantaged are not fully receiving these benefits. Public policy, insurance and medicaid groups must be made aware of these preventative measures and strategies developed to implement them.  相似文献   
2.
Economists have become increasingly interested in hypotheses from sociobiology as a source of inspiration for filling gaps in the economic model of behavior. To avoid borrowing eclectically and arbitrarily from neighboring disciplines, this paper attempts to outline in a systematic way the similarities and differences between the approaches taken in economics and sociobiology. In doing so, special attention is given to an empirical theory of preferences that is lacking in economics. Here, inspiration from sociobiology would seem to be particularly useful. The considerations in the paper suggest that sociobiological arguments may indeed be helpful, albeit at a very elementary level only. A more comprehensive theory cannot ignore the influences of innate learning mechanisms in higher living beings. An elaborated theory of preferences in economics will have to acknowledge and incorporate insights from behavioral psychology.  相似文献   
3.
4.
5.
6.
To be efficient, logistics operations in e‐commerce require warehousing and transportation resources to be aligned with sales. Customer orders must be fulfilled with short lead times to ensure high customer satisfaction, and the costly under‐utilization of workers must be avoided. To approach this ideal, forecasting order quantities with high accuracy is essential. Many drivers of online sales, including seasonality, special promotions and public holidays, are well known, and they have been frequently incorporated into forecasting approaches. However, the impact of weather on e‐commerce operations has not been rigorously analyzed. In this study, we integrate weather data into the sales forecasting of the largest European online fashion retailer. We find that sunshine, temperature, and rain have a significant impact on daily sales, particularly in the summer, on weekends, and on days with extreme weather. Using weather forecasts, we have significantly improved sales forecast accuracy. We find that including weather data in the sales forecast model can lead to fewer sales forecast errors, reducing them by, on average, 8.6% to 12.2% and up to 50.6% on summer weekends. In turn, the improvement in sales forecast accuracy has a measurable impact on logistics and warehousing operations. We quantify the value of incorporating weather forecasts in the planning process for the order fulfillment center workforce and show how their incorporation can be leveraged to reduce costs and increase performance. With a perfect information planning scenario, excess costs can be reduced by 11.6% compared with the cost reduction attainable with a baseline model that ignores weather information in workforce planning.  相似文献   
7.
中德婚姻市场供需情况的比较研究   总被引:11,自引:0,他引:11  
本文从概念、形成机制、度量方法、后果及其解决途径等方面探讨了婚姻挤压问题 ,考虑到婚姻挤压对婚姻寿命、初婚人数及其性别差异的影响而创立了婚姻寿命指数与初婚挤压指数两指标 ,提出了婚姻市场类型的划分标准。通过对中德两国婚姻市场的历史与现状的考察 ,揭示了中德两国婚姻挤压产生的原因、类型、差异和未来的变化趋势 ,并对如何化解中国未来婚姻市场的供求矛盾提出了对策与建议  相似文献   
8.
We present APproximated Exhaustive Search (APES), which enables fast and approximated exhaustive variable selection in Generalised Linear Models (GLMs). While exhaustive variable selection remains as the gold standard in many model selection contexts, traditional exhaustive variable selection suffers from computational feasibility issues. More precisely, there is often a high cost associated with computing maximum likelihood estimates (MLE) for all subsets of GLMs. Efficient algorithms for exhaustive searches exist for linear models, most notably the leaps‐and‐bound algorithm and, more recently, the mixed integer optimisation (MIO) algorithm. The APES method learns from observational weights in a generalised linear regression super‐model and reformulates the GLM problem as a linear regression problem. In this way, APES can approximate a true exhaustive search in the original GLM space. Where exhaustive variable selection is not computationally feasible, we propose a best‐subset search, which also closely approximates a true exhaustive search. APES is made available in both as a standalone R package as well as part of the already existing mplot package.  相似文献   
9.
Theory and Decision - In contrast to the assumptions of standard economic theory, recent experimental evidence shows that the income of peers has a systematic impact on observed degrees of risk...  相似文献   
10.
Permanent income (PI) is an enduring concept in the social sciences and is highly relevant to the study of inequality. Nevertheless, there has been insufficient progress in measuring PI. We calculate a novel measure of PI with the German Socio-Economic Panel (SOEP) and U.S. Panel Study of Income Dynamics (PSID). Advancing beyond prior approaches, we define PI as the logged average of 20+ years of post-tax and post-transfer (“post-fisc”) real equivalized household income. We then assess how well various household- and individual-based measures of economic resources proxy PI. In both datasets, post-fisc household income is the best proxy. One random year of post-fisc household income explains about half of the variation in PI, and 2–5 years explain the vast majority of the variation. One year of post-fisc HH income even predicts PI better than 20+ years of individual labor market earnings or long-term net worth. By contrast, earnings, wealth, occupation, and class are weaker and less cross-nationally reliable proxies for PI. We also present strategies for proxying PI when HH post-fisc income data are unavailable, and show how post-fisc HH income proxies PI over the life cycle. In sum, we develop a novel approach to PI, systematically assess proxies for PI, and inform the measurement of economic resources more generally.  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