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1.
Pregnant women are likely to be sensitive to daily fluctuations in nutritional intake. To see if income constraints at the end of the month limit food consumption and trigger health problems, we examine how the date that benefits are issued for the Supplemental Nutrition Assistance Program (SNAP) changes the probability that a woman will go to the Emergency Room (ER) for pregnancy-related conditions using administrative data from SNAP and Medicaid from Missouri for 2010–2013. SNAP benefits in Missouri are distributed from the 1st through the 22nd day of the month based on the birth month and the first letter of the last name of the head of the household, making timing of SNAP issuance exogenous. We estimate probit models of the calendar month and SNAP benefit month on the probability of a pregnancy-related ER visit for women age 17–45, or the sample at risk of being pregnant. We also examine the relationship between SNAP benefit levels and ER visits. We found that women who received SNAP benefits in the second or third week of the calendar month were less likely to receive pregnancy-related care through the ER in the week following benefit receipt. Results suggest that SNAP benefits might be related to patterns of pregnancy-related medical care accessed through the ER. Since SNAP issuance date is within state control in the United States, states may want to consider the health effects of their choice.  相似文献   
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The integration of dance into K–12 curriculum can help students to learn better, encouraging deeper exploration and active engagement with content knowledge. The purpose of this intervention study was to determine how the integration of dance and social studies with an anthropological framework affects student learning of content knowledge in social studies, as well as student attitude toward the topic. An anthropological framework was implemented to foster respectful investigation of culture. As a supplement to a sixth-grade unit on Ancient Egypt, the experimental group received four intervention lessons, incorporating creative dance. Results show that at posttest the intervention group had significantly higher content knowledge than the control group, and qualitative student responses from the intervention group suggest extremely positive feelings toward experiences in the program. This suggests that incorporating dance into sixth-grade social studies with an anthropological framework can encourage student exploration and increase understanding of content.  相似文献   
3.
Aggressive behavior has been well studied in terms of interindividual differences among aggressors and victims, but has been understudied, especially within naturalistic contexts, in terms of aggressor–victim relationships. The social relations model (SRM) is a powerful conceptual and analytic tool for studying dyadic phenomena, and we describe the use of multivariate SRM to study aggression. Boys and girls (N = 210) in middle schools (sixth and seventh grades) completed a newly created dyadic aggression and victimization inventory (DAVI). Results support the reliability and validity of the DAVI in assessing inter‐individual and inter‐dyadic differences in aggression and victimization. Occurrences of aggression were accounted for primarily by inter‐dyadic variability, indicating the importance of considering aggressor–victim relationships. We discuss the implications of this relationship focus for future research and intervention efforts.  相似文献   
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Has civil society declined in the United States in the past 20 years? Multiple indicators suggest evidence for decline. This paper questions Robert Putnam's generational explanation for decline and suggests an alternative explanation, namely the structural economic transformation of the U.S. and how it has been managed. Individuals' perceptions of economic distress have increased since 1972 and are related to changes in indicators of civil society, including associational memberships, trust, anomia, and espoused racial and gay tolerance. Economic distress is also related to political interest and participation. Other consequences of an eroding civil society are discussed, including rising crime and inhibited economic productivity

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6.
Measuring a statistical model's complexity is important for model criticism and comparison. However, it is unclear how to do this for hierarchical models due to uncertainty about how to count the random effects. The authors develop a complexity measure for generalized linear hierarchical models based on linear model theory. They demonstrate the new measure for binomial and Poisson observables modeled using various hierarchical structures, including a longitudinal model and an areal‐data model having both spatial clustering and pure heterogeneity random effects. They compare their new measure to a Bayesian index of model complexity, the effective number pD of parameters (Spiegelhalter, Best, Carlin & van der Linde 2002); the comparisons are made in the binomial and Poisson cases via simulation and two real data examples. The two measures are usually close, but differ markedly in some instances where pD is arguably inappropriate. Finally, the authors show how the new measure can be used to approach the difficult task of specifying prior distributions for variance components, and in the process cast further doubt on the commonly‐used vague inverse gamma prior.  相似文献   
7.
Stewart D Hodges 《Omega》1976,4(6):699-709
This paper discusses a number of problems which arise in the implementation of portfolio selection models. It is suggested that the effect of errors and biases in expected return forecasts can be reduced by using these forecasts to modify a prior distribution which leads to minimal trading activity. Efficient diversification across industry groups is hampered by the difficulties of predicting covariances. The use of a selection model through time raises the issues of revising forecasts and of the relationships upon which the appropriate investment horizon and portfolio turnover depend. Last, consideration is given to the conflicts which may exist between management objectives and the mean-variance criterion used by most models.  相似文献   
8.
As U.S. manufacturing and production industries have declined, the growth of the care sector has increasingly become an important source of jobs for workers without a college degree. Often requiring some form of postsecondary credentialing, many care occupations can provide better wages, job stability, and possible upward mobility for less educated workers. However, employment patterns in paid care work are both gendered and racialized: women and workers of color are overrepresented in care occupations with fewer entry barriers, benefits, and lower pay. Although these patterns are well documented, the mechanisms producing them are less well understood. Using event history analysis and the National Longitudinal Survey of Youth (NLSY79), this study evaluates the explanatory power of neoclassical economic, status attainment, and social closure theories of occupational segregation for black women’s and men’s greater hazard or “risk” of entering care occupations, relative to white workers. Net of individual and closure mechanisms, significant residual effects suggest labor market discrimination remains a primary explanation for the over-representation of black workers in less credentialed care jobs with fewer benefits.  相似文献   
9.
To protect and secure food resources for the United States, it is crucial to have a method to compare food systems’ criticality. In 2007, the U.S. government funded development of the Food and Agriculture Sector Criticality Assessment Tool (FASCAT) to determine which food and agriculture systems were most critical to the nation. FASCAT was developed in a collaborative process involving government officials and food industry subject matter experts (SMEs). After development, data were collected using FASCAT to quantify threats, vulnerabilities, consequences, and the impacts on the United States from failure of evaluated food and agriculture systems. To examine FASCAT's utility, linear regression models were used to determine: (1) which groups of questions posed in FASCAT were better predictors of cumulative criticality scores; (2) whether the items included in FASCAT's criticality method or the smaller subset of FASCAT items included in DHS's risk analysis method predicted similar criticality scores. Akaike's information criterion was used to determine which regression models best described criticality, and a mixed linear model was used to shrink estimates of criticality for individual food and agriculture systems. The results indicated that: (1) some of the questions used in FASCAT strongly predicted food or agriculture system criticality; (2) the FASCAT criticality formula was a stronger predictor of criticality compared to the DHS risk formula; (3) the cumulative criticality formula predicted criticality more strongly than weighted criticality formula; and (4) the mixed linear regression model did not change the rank‐order of food and agriculture system criticality to a large degree.  相似文献   
10.
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