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51.
Constructing spatial density maps of seismic events, such as earthquake hypocentres, is complicated by the fact that events are not located precisely. In this paper, we present a method for estimating density maps from event locations that are measured with error. The estimator is based on the simulation–extrapolation method of estimation and is appropriate for location errors that are either homoscedastic or heteroscedastic. A simulation study shows that the estimator outperforms the standard estimator of density that ignores location errors in the data, even when location errors are spatially dependent. We apply our method to construct an estimated density map of earthquake hypocenters using data from the Alaska earthquake catalogue.  相似文献   
52.
Simple, closed form saddlepoint approximations for the distribution and density of the singly and doubly noncentral F distributions are presented. Their overwhelming accuracy is demonstrated numerically using a variety of parameter values. The approximations are shown to be uniform in the right tail and the associated limitating relative error is derived. Difficulties associated with some algorithms used for exact computation of the singly noncentral F are noted.  相似文献   
53.
The focus of recent stratification research demonstrates increasing recognition of the structured nature of social inequality. Among the forms these efforts have taken has been the development of a number of models drawing attention to the importance of various labor market decisions or cleavages. The crucial role which restricted labor mobility must play in maintaining these cleavages, while largely untested, has long been recognized. We argue that analysis of the patterns of job sequencing can be used to draw important inferences regarding the existence and character of labor market structures. From this premise, we use job transition data to test a number of propositions derived from dual economy theory, relating to the extent of intersectoral moves and the patterns of intersectoral and intrasectoral moves. Using log-linear methods, we find the hypothesized restricted evidence of intersectoral job shifts and also find patterns of intrasectoral moves indicative of the pervasiveness of rigidly structured internal labor markets in the core. While these results are consistent with a dualistic interpretation, they are equally as consistent with any model emphasizing the existence of strong intrafirm and intraindustry job structures.  相似文献   
54.
Marital fertility in 54 Prussian cities and 407 Prussian Kreise (administrative areas) is analyzed using unusually rich and detailed socioeconomic and demographic data from eight quinquennial census between 1875 and 1910. Pooled cross-section time series methods are used to examine influences on marital fertility level and on marital fertility decline, focusing particularly on fertility differences according to level of urbanization. Increases in female labour force participation rate and income, the growth of financial services and communications, improvement in education, and reduction in infant mortality account for most of the marital fertility decline in 19th century Prussia. In 1875, rural and urban fertility were similar but by 1910, urban fertility was far lower than rural in part because the values of some of these variables changed more rapidly in the cities, and in part because some of these variables had stronger effects in urban settings.  相似文献   
55.
We consider the calculation of power functions in classical multivariate analysis. In this context, power can be expressed in terms of tail probabilities of certain noncentral distributions. The necessary noncentral distribution theory was developed between the 1940s and 1970s by a number of authors. However, tractable methods for calculating the relevant probabilities have been lacking. In this paper we present simple yet extremely accurate saddlepoint approximations to power functions associated with the following classical test statistics: the likelihood ratio statistic for testing the general linear hypothesis in MANOVA; the likelihood ratio statistic for testing block independence; and Bartlett's modified likelihood ratio statistic for testing equality of covariance matrices.  相似文献   
56.
When using data envelopment analysis (DEA) as a benchmarking technique for nursing homes, it is essential to include measures of the quality of care. We survey applications where quality has been incorporated into DEA models and consider the concerns that arise when the results show that quality measures have been effectively ignored. Three modeling techniques are identified that address these concerns. Each of these techniques requires some input from management as to the proper emphasis to be placed on the quality aspect of performance. We report the results of a case study in which we apply these techniques to a DEA model of nursing home performance. We examine in depth not only the resulting efficiency scores, but also the benchmark sets and the weights given to the input and output measures. We find that two of the techniques are effective in insuring that DEA results discriminate between high and low quality performance.  相似文献   
57.
An examination of 1970–1980 census data for suburban Chicago indicates that, within the context of persisting inequities, causal links between community characteristics and status change vary by initial status. Individual change in the relative rankings of initially affluent communities is a direct function of housing age and location; residential development and changes in population size have little or no effect on this process. In contrast, cyclical growth is the primary determinant of status change among places of lesser initial affluence. Within the larger context of centrifugal drift and age-related growth cycles, stronger growth and resulting status improvements occur in accessible, underdeveloped newer places that, due to recent suburbanization, have already attained somewhat higher rankings.  相似文献   
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59.
The probability of first marriage for men who graduated from Wisconsin high schools in 1957 was analyzed with respect to their Social Security earnings records, Wisconsin income tax reports for parents, and other variables. The findings provide no support for Easterlin's hypothesis that marriage will occur earlier when young men judge their economic prospects favorably with respect to their parents' income. However, young men's earnings and time spent in schooling to increase them were found to be important influences on marriage timing. Additional schooling had little effect net of the time it absorbed.  相似文献   
60.
Anecdotal reports have suggested that the use and abuse of methamphetamine is increasing in the United States. To date, however, few scholarly works have explored the prevalence and correlates of methamphetamine use in the United States. To address this limitation, a secondary analysis was undertaken with data collected through the Arrestee Drug Abuse Monitoring (ADAM) Program. An examination of methamphetamine-positive rates among ADAM arrestees interviewed between 1991 and 2001 identified that its use is concentrated within the Western part of the United States. Supplementary analyses of Sacramento arrestees indicated that 71% were diagnosed as needing some form of alcohol or other drug treatment. Compared to those arrestees who were detected methamphetamine-negative, methamphetamine-positive arrestees in Sacramento were three times as likely to be white and to have been diagnosed in need of drug treatment. Implications for drug control policy are discussed.  相似文献   
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