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591.
What accounts for the differences in the kinds of communities within the metropolis in which members of different racial and ethnic groups live? Do socioeconomic advancement and acculturation provide greater integration with whites or access to more desirable locations for minority-group members? Are these effects the same for Asians or Hispanics as for blacks? Does suburbanization offer a step toward greater equality in the housing market, or do minorities find greater discrimination in the suburban housing market? Data from 1980 for five large metropolitan regions are used to estimate "locational-attainment models, " which evaluate the effects of group members’ individual attributes on two measures of the character of their living environment: the socioeconomic standing (median household income) and racial composition (proportion non-Hispanic white) of the census tract where they reside. Separate models predict these outcomes for whites, blacks, Hispanics, and Asians. Net of the effects of individuals’ background characteristics, whites live in census tracts with the highest average proportion of white residents and the highest median household income. They are followed by Asians and Hispanics, and-at substantially lower levels-blacks. Large overall differences exist between city and suburban locations; yet the gap between whites and others is consistently lower in the suburbs than in the cities of these five metropolitan regions.  相似文献   
592.

Background

Substance use during pregnancy is a major public health concern, stemming from potential physical and psychosocial harms to both the mother and child.

Purpose

To understand women’s experiences using substances during pregnancy and the reasons that women continue and/or discontinue using substances.

Methods

Focus groups were conducted with women who attended an early intervention program for pregnant or parenting women with substance use issues.

Results

Women identified that external and internal stressors, feelings of guilt and low-self efficacy, and a lack of understanding of the scientific and medical consequences of substance use contributed to their continued substance use. Conversely, women highlighted the importance of high self-efficacy and the quality of relationships when trying to make positive changes to their substance use during pregnancy.

Conclusions

Recommendations are proposed for easier access to and more comprehensive services. Healthcare professionals and service providers should offer non-judgmental care by building high-quality relationships with pregnant women with substance use issues, to increase these women’s self-efficacy and empower them to discontinue substance use.  相似文献   
593.
There are long‐standing concerns over low fertility levels in Europe and an increasingly important debate on the extent to which migration can compensate for below‐replacement fertility. To inform this debate, a wide array of indicators have been developed to assess the joint influence of fertility, mortality, and migration on birth replacement and intergenerational replacement. These indicators are based on various models and assumptions and some are particularly data demanding. In this article we propose a simple method to assess how far migration alters the extent of replacement for a birth cohort as it ages. We term the measure the overall replacement ratio (ORR). It is calculated by taking the size of a female birth cohort at selected ages divided by the average size of the cohorts of mothers in the year of birth. We present estimates of the ORR for a range of European countries representing different replacement regimes. We demonstrate that for many countries net migration has become a key factor in their population trends during the last few decades.  相似文献   
594.
The development of a composite indicator (CI) over a set of individual indicators is worthwhile in case the methodological aggregation process is sound and the results are clear. It can then be used as a powerful tool for performance evaluation, benchmarking, and decision making. In this respect, data envelopment analysis (DEA), as a self appraisal technique, has recently received considerable attention in the construction of CIs for policy analysis and public communication. However, due to the ever increasing complexity of numerous performance evaluation problems, more and more potential indicators might be developed to represent an evaluation activity in a more comprehensive way. These indicators might also belong to different categories and further be linked to one another constituting a multilayer hierarchical structure. Simply treating all the indicators to be in the same layer as is the case in the basic DEA model thereby ignores the information on their hierarchical structure, and further leads up to weak discriminating power and unrealistic weight allocations. To overcome this limitation, a multiple layer DEA-based CI model is developed in this study to embody a hierarchical structure of indicators in the DEA framework, and both its primal and dual form are realized. The proposed model is illustrated by constructing a composite road safety performance index for a set of European countries.  相似文献   
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Scientific ideas neither arise nor develop in a vacuum. They are always nutured against a background of prior, partially conflicting ideas. Systemic hypothesistesting is the problem of testing scientific hypotheses relative to various systems of background knowledge. This paper shows how the problem of systemic hypothesis-testing (Sys HT) can be systematically expressed as a constrained maximimization problem. It is also shown how the error of the third kind (E III) is fundamental to the theory of Sys HT.The error of the third kind is defined as the probability of having solved the ‘wrong’ problem when one should have solved the ‘right’ problem. This paper shows howE III can be given both a systematic as well as a systemic treatment. Sys HT gives rise to a whole host of new decision problems, puzzles, and paradoxes.  相似文献   
598.
ABSTRACT: It is noticed that in both theoretical and empirical analyses concerning the relationship between corporatism and economic performance, the role of government is kept rather implicit. This article aims to incorporate government into the analysis in a more explicit way by analyzing whether government policies differ between corporatist and non-corporatist countries. The empirical results of the research reveal that corporatist countries are not only characterized by centralization or coordination of wage bargaining, but also by relatively high government expenditure, tax revenues, a higher ratio of active to passive labour market policies and also higher average unemployment benefits.  相似文献   
599.
We study adaptive importance sampling (AIS) as an online learning problem and argue for the importance of the trade-off between exploration and exploitation in this adaptation. Borrowing ideas from the online learning literature, we propose Daisee, a partition-based AIS algorithm. We further introduce a notion of regret for AIS and show that Daisee has 𝒪 ( T ( log T ) 3 4 ) cumulative pseudo-regret, where T $$ T $$ is the number of iterations. We then extend Daisee to adaptively learn a hierarchical partitioning of the sample space for more efficient sampling and confirm the performance of both algorithms empirically.  相似文献   
600.
In this paper, I study the production of academic research by economics departments and economists. Worldwide rankings are provided based on both citations and publications. These rankings reveal a dominant position of the United States in the production of economics literature. Over time, however, the extent of this dominance is decreasing. (JEL: A10, A14)  相似文献   
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