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   115篇
  免费   5篇
管理学   17篇
人口学   8篇
理论方法论   9篇
社会学   34篇
统计学   52篇
  2023年   1篇
  2022年   2篇
  2021年   2篇
  2020年   3篇
  2019年   6篇
  2018年   6篇
  2017年   4篇
  2016年   3篇
  2015年   1篇
  2014年   2篇
  2013年   56篇
  2012年   6篇
  2011年   2篇
  2010年   1篇
  2009年   3篇
  2008年   1篇
  2007年   1篇
  2006年   5篇
  2005年   1篇
  2003年   2篇
  2002年   2篇
  2001年   1篇
  1999年   1篇
  1997年   1篇
  1996年   1篇
  1992年   1篇
  1991年   1篇
  1985年   1篇
  1983年   1篇
  1982年   1篇
  1978年   1篇
排序方式: 共有120条查询结果,搜索用时 171 毫秒
71.
This study sought to develop a set of easily obtainable, relevant measures of a community's condition that could be used to guide its suicide prevention efforts. Existing data were gathered across 159 Georgia counties for nine potential social indicators (rates of net migration, divorce, unemployment, violent crimes reported, driving under the influence of alcohol or drugs [DUI] crashes, high school dropouts, Temporary Assistance for Needy Families [TANF], percentage of population aged 65 or older, and percentage of population who are white males) that had been chosen by the communities. Data on the social indicators from 1995 through 1999 were averaged and analyzed to determine their correlation with aggregated 5-year county suicide rates. Results of multivariate modeling procedures showed number of DUI crashes and percentage of the population aged 65 or older to be significant correlates of the suicide rate, controlling for other potential indicators. These preliminary data may provide a useful model of a county's 5-year suicide rate among counties reporting 20 or more suicides. Research with additional indicators and in other states will help determine the generalizability of these findings to other communities.  相似文献   
72.
A country's economy and its energy base have a complex yet strong relationship. As a result the provisioning of an increasing quanta of energy is a vital pre-requisite for the economic growth of a country. With certain exceptions it has been found from a study of the per capita electric energy generation and per capita income that between 0·7 and 2 units of electric energy are required for generation of one unit of income. The exact relationship will vary from country to country depending on the particular energy-mix, the extent of industrialization and the energy efficiency of the economy. In the case of India, with the increasing contribution being made by the manufacturing, mining, transportation and communication sectors to the gross national product, the linkage between energy consumption and the deflated GNP are specific and strong. This paper outlines the methodology by which the relationship has been modelled and a forecast made of the energy demand.  相似文献   
73.
An important aspect that affects the effectiveness of ergonomic programs is that inefficient mechanical functioning start at an early age and that back pain and posture problems are already evident in children. Children, from a very early age, as well as adults spend an ever increasing amount of their time in front of computer and television screens. The cumulative effect of this sedentary lifestyle leads to improper posture, as well as inefficient and harmful movement patterns and loss of basic physical skills. Physical Education course should deal not only with sports and physical activities, but also with broader aspects of life-skills and physical functionality. It should offer a solution to the modern technology-based society. Keeping this in perspective, Ergonomics content was introduced in Physical Education Teacher's Guide in Rwandan schools with an aim in preventing musculoskeletal disorder in children.  相似文献   
74.
We examine the quasi‐randomization of alcohol consumption created by state‐level alcohol prohibition laws passed in the United States in the early part of the twentieth century. Using a large dataset of World War II enlistees, we exploit the differential timing of these laws to examine their effects on adult educational attainment, obesity, and height. We find statistically significant effects for education and obesity that do not appear to be the result of pre‐existing trends. Our findings add to the growing body of economic studies that examine the long‐run impacts of in utero and childhood environmental conditions. (JEL I18, D10, N41, N42)  相似文献   
75.
Existing research focuses on the positive returns to operational performance of firms’ supply chain integration (SCI) with suppliers, buyers, and customers. We draw on differentiation‐integration duality and contingency theory to suggest that manufacturing firms should seek to achieve both integration through supply chain coordination activities and differentiation through modularity‐based manufacturing practices (MBMP). Using a sample of 261 manufacturing firms, we identify an inverse U‐shaped relationship between SCI and operational performance. Furthermore, we find support for the importance of differentiation‐integration duality as a fit between high levels of SCI and high levels of MBMP results in enhanced operational performance. We find support for a contingency perspective as fit is especially critical at higher levels of environmental uncertainty. Implications for theory, practice, and further research are suggested.  相似文献   
76.
In this paper the study of relative bias (RB), exact variance and mean square error (MSE) of the maximum likelihood estimators of the exponential distribution under type I progressive censoring with changing failure rates is considered. A minimum mean square error (MMSE) estimator for the parameter at each stage is proposed. The numerical evalution of their relative performance is made for selected values of n and p. Further results concerning group-censoring, total expected waiting time and optimal spacings of the times of censoring are derived and results obtained by Kendell and Anderson (1971) are deduced as special cases.  相似文献   
77.
A procedure is given for obtaining a random width confidence interval for the largest reliability of k Weibull populations. The procedure does not identify the populations for which the reliability would be a maximum. The maximum likelihood estimators or the simplified linear estimators of the reliability based on type II censored data are used. The cases considered include unknown shape parameters being equal or unequal. Simultaneous confidence intervals for the k reliabilities are also obtained. Tables for the lower and upper limits in selected cases are constructed using Monte Carlo methods.  相似文献   
78.
In this article we discuss multistage group screening in which group-factors contain differing number of factors. We describe a procedure for grouping the factors in the absence of concrete prior information, so that the relative testing cost is minimal. It Is shown that under quite general conditions, these designs will require fewer runs than the equivalent designs in which the group-factors contain same number of factors.  相似文献   
79.
Consider k( k ≥ 1) independent Weibull populations and a control population which is also Weibull. The problem of identifying which of these k populations are better than the control using shape parameter as a criterion is considered. We allow the possibility of making at most m(0 ≤ m < k) incorrect identifications of better populations. This allowance results in significant savings in sample size. Procedures based on simple linear unbiased estimators of the reciprocal of the shape parameters of these populations are proposed. These procedures can be used for both complete and Type II-censored samples. A related problem of confidence intervals for the ratio of ordered shape parameters is also considered. Monte Carlo simulations as well as both chi-square and normal approximations to the solutions are obtained.  相似文献   
80.
Consider k(k ≥ 2) two-parameter Meibull populations. Using type II censored data we want to select a best population. Me have proposed procedures which can be used for maximum likelihood estimators or simplified linear estimators of Che unknown parameters. The ranking of the populations is done by comparing their reliabilities at certain fixed time or by comparing their 2-eh quantiles. In selected cases, the constants needed for the procedures are tabulated using Monte Carlo methods.  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