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101.
This article develops a simultaneous supply-and-demand model of the American steel industry for the years 1920–1972. The analysis takes into account the differences between published (book) and actual transactions prices. The model also provides for the oligopolistic nature of the steel market and the possibility that price may deviate from marginal cost. The demand results are in conformance with theory and earlier empirical work, but on the supply side some problems exist with the input price parameters. A reason for this situation may be that the steel industry is a large user of some inputs, making the relationship between steel output and these factor prices simultaneous.  相似文献   
102.
In this paper a neat construction is provided for three new families of group divisible designs that generalize some designs from Clatworthy's table of the only 11 designs with two associate classes that have block size four, three groups, and replication numbers at most 10. In each case (namely, λ1=4λ1=4 and λ2=5λ2=5, λ1=4λ1=4 and λ2=2λ2=2, and λ1=8λ1=8 and λ2=4λ2=4), we have proved that the necessary conditions found are also sufficient for the existence of such GDD's with block size four and three groups, with one possible exception.  相似文献   
103.
A survey of New Zealand university and polytechnic libraries indicates what proportions of library e-journal holdings have archival rights or perpetual access clauses. The author then analyzes licenses from three universities for terms, permissions, and other details. The research indicates that less than 20% of the online holdings for most New Zealand educational libraries had a print duplicate, archive, or perpetual access right. Licenses failed to address these access and rights issues in 70% of the cases surveyed. The issues of long-term access to licensed materials are addressed in less than 30% of licenses and only by providers that are offering them.  相似文献   
104.
In May 2012, the Committee of Health and Medicinal Products issued a concept paper on the need to review the points to consider document on multiplicity issues in clinical trials. In preparation for the release of the updated guidance document, Statisticians in the Pharmaceutical Industry held a one‐day expert group meeting in January 2013. Topics debated included multiplicity and the drug development process, the usefulness and limitations of newly developed strategies to deal with multiplicity, multiplicity issues arising from interim decisions and multiregional development, and the need for simultaneous confidence intervals (CIs) corresponding to multiple test procedures. A clear message from the meeting was that multiplicity adjustments need to be considered when the intention is to make a formal statement about efficacy or safety based on hypothesis tests. Statisticians have a key role when designing studies to assess what adjustment really means in the context of the research being conducted. More thought during the planning phase needs to be given to multiplicity adjustments for secondary endpoints given these are increasing in importance in differentiating products in the market place. No consensus was reached on the role of simultaneous CIs in the context of superiority trials. It was argued that unadjusted intervals should be employed as the primary purpose of the intervals is estimation, while the purpose of hypothesis testing is to formally establish an effect. The opposing view was that CIs should correspond to the test decision whenever possible. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
105.
If one subgroup of individuals in a population has a higher death rate than the others, then over time the surviving population will include a larger share of those with the lower death rate. As a result, the aggregate average death rate for this increasingly more robust population will decline. This conclusion, however, can be drawn only for nonrecurrent events experienced by populations that do not exchange members with one another--that is, for noninteracting populations. Studies of changes in marital status, labor force activity, residential location, and active life, for example, all should focus on patterns of recurrent events among interacting populations (that is, multistate populations). Selection arising from heterogeneity will occur, but the consequences for average measures become unpredictable a priori. This paper explores such aspects of the selection effects of heterogeneity in multistate populations and illuminates some of their consequences for commonly used rates.  相似文献   
106.
We assess the impact of maternal sense of mastery and maternal working conditions on maternal perceptions of children's behavior problems as a means to study the transmission of social control across generations. We use a sample of 521 employed mothers and their four-to six-year-old children from the National Longitudinal Survey's Youth Cohort in 1986. Regarding working conditions, we consider mother's hourly wage, work hours, and job content including involvement with things (vs. people), the requisite level of physical activity, and occupational complexity. We also consider maternal and child background and current family characteristics, including marital status, family size, and home environment. Maternal mastery was related to fewer reported behavior problems among children. Lower involvement with people and higher involvement with things, as well as low physical activity, were related significantly to higher levels of perceived problems. In addition, recent changes in maternal marital status, including maternal marriage or remarriage, increased reports of problems; stronger home environments had the opposite effect. We interpret these findings as suggesting how maternal experiences of control in the workplace and personal resources of control can influence the internalization of control in children.  相似文献   
107.
Minimum distance statistics for testing inequality restrictions on the mean vector of a multivariate normal population are considered and are shown to be equivalent to certain induced (or intersection) test statistics. Tests based on these statistics are shown to be admissible.  相似文献   
108.
109.
Although smoking has been linked to various causes of death, there is no systematic account of the underlying and multiple cause-of-death distributions associated with various smoking statuses. We analyze such patterns by age and gender for the USA in 1986. Our study is based on a one-percent random sample of decedents 25 and over in the USA for whom survey data from informants were linked to death certificate data. Smoking is related to several underlying causes of death, the most common being circulatory diseases. Lung cancer is less prevalent than circulatory diseases or other cancers among ever smokers. Multiple medical conditions are common for both smokers and nonsmokers, but particular combinations vary among persons with different smoking statuses. Former smokers who quit soon before death and were under frequent medical care are most likely to have had lung cancer. Amount of smoking is tied to variations in cause-of-death patterns. Differences by age and gender are not substantial, although other cancers appear frequently for both smokers and non-smokers among women. The distribution of medical causes of death for ever smokers is not radically different from that of never smokers. However, differences in cause patterns are seen when smoking statuses are detailed by amount of smoking and timing of quitting. These similarities and differences in cause patterns must be related to the fundamental fact that the average smoker will die earlier than the average nonsmoker. Such findings should especially influence programs for diseases whose links to smoking have been underestimated.  相似文献   
110.
The federally funded Elderly Nutrition Program is mandated to serve elders in greatest social and economic need. Yet researchers have concluded that the program underserves certain groups of elders, including those who are socially impaired and homeless and members of ethnic and other minority groups. This paper reviews the issues involved in serving elders in greatest social and economic need and suggests that reaching all of these elders with program services is not only a laudable goal but also, based on innovative models briefly described, is clearly achievable.  相似文献   
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