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991.
Journal of Risk and Uncertainty - As health care becomes increasingly personalized to the needs and values of individual patients, informational interventions that aim to inform and debias consumer...  相似文献   
992.
A pre‐pack is a collection of items used in retail distribution. By grouping multiple units of one or more stock keeping units (SKU), distribution and handling costs can be reduced; however, ordering flexibility at the retail outlet is limited. This paper studies an inventory system at a retail level where both pre‐packs and individual items (at additional handling cost) can be ordered. For a single‐SKU, single‐period problem, we show that the optimal policy is to order into a “band” with as few individual units as possible. For the multi‐period problem with modular demand, the band policy is still optimal, and the steady‐state distribution of the target inventory position possesses a semi‐uniform structure, which greatly facilitates the computation of optimal policies and approximations under general demand. For the multi‐SKU case, the optimal policy has a generalized band structure. Our numerical results show that pre‐pack use is beneficial when facing stable and complementary demands, and substantial handling savings at the distribution center. The cost premium of using simple policies, such as strict base‐stock and batch‐ordering (pre‐packs only), can be substantial for medium parameter ranges.  相似文献   
993.
This research examines the role of social and economic factors in the past selection of destinations made by migrants living in Rhode Island. Results indicate that social ties play a more important role in the selection of destinations with low levels of opportunity than they do in the movement to high opportunity areas. An important aspect of the study was the simultaneous investigation of both objective and subjective measures of social and economic factors in the selection of low and high growth destinations. The analysis suggests that the simultaneous consideration of objective and subjective factors provides a more refined accounting of the potential influence of social and economic factors in the selection of destinations. The findings hold when age is introduced as a control.  相似文献   
994.
Utilizing panel data on families, estimates are made of the effects of children on asset accumulation, asset composition, consumption, and family income. Young children are found to depress savings for young families but to increase savings for marriages of duration greater than five years. The principal channel through which children act to reduce savings is the decline in female earnings associated with the child-induced withdrawal of wives from the labor force. Family consumption actually decreases with the birth of a child, but this reduction is insufficient, for young families, to offset the fall in income. For families in which the wife does not work the estimates suggest that savings may actually increase with children.  相似文献   
995.
The history of the official U. S. projections of population and house-holds in recent decades is briefly reviewed, with particular attention to methodology and the relation of the methodology to the accuracy of the projections. The introduction of the cohort-component procedure in the 1930’s opened the way for separate analysis of the trend of the components of births, deaths, and net immigration in connection with making population projections. As a further development, the period-fertility method of projecting births gave way in the 1960’s to the cohort-fertility method. Consideration is now being given to various methods involving parity-progression procedures. Some alternative methods and problems of measuring the accuracy of population projections are then considered. The percent “error” in the projected population growth, by components and age, and the range from high to low expressed as a percent should also be examined in addition to the percent “error” in the total population. However accuracy is measured, the projections made in the 1930’s and 1940’s were often wide of the mark, and those made in the 1950’s and 1960’s failed to anticipate the sharp changes which occurred, even though the actual figures usually fell within the range projected. Elaboration of projection methodology has not resulted in any great increase in the precision of the projections, largely because birth rates have fluctuated widely, and the fluctuations have proven difficult, if not impossible, to predict. The projections of households have had a roughly similar history, and the methods and problems of evaluation are somewhat similar. Their development has been characterized by the introduction of alternative and changing “headship” rates and increasing disaggregation of the data and procedures. The paper concludes with some generalizations based on U. S. experience. Although refinement of methods may contribute little to accuracy, accuracy is only one aspect of the usefulness of projections. The need for conditional projections and their analytical usefulness are such that there is no question that we should confidently continue to make them.  相似文献   
996.
This study examines length of residence for movers—that subsection of the population which accounts for the high mobility rates in the United States. The propensity for repeated migration is studied in relation to economic opportunities and previous familial and personal contacts. The results indicate no influence of economic opportunities on duration of residence. This finding is consistent with recent research that indicates economic conditions are not a general stimulus for out-migration, although they are for in-migration. On the other hand, length of residence is found to be longer where previous familial and personal contacts existed. Overall, the results provide additional evidence of the importance of social, as opposed to strictly economic, variables in the migration process.  相似文献   
997.
Urbanization and the fertility transition in Ghana   总被引:2,自引:0,他引:2  
This paper examines the way in which migration and urban residence operate to alter fertility outcomes. While urban-rural fertility differentials have long been established for most developing societies, the nature of these differences among migrants and between migrants and those of succeeding generations is not well understood. The evidence presented here suggests that rural-urban migration and urbanization may contribute positively to processes of fertility transition. Using data from the 1998 Kumasi Peri-Urban Survey, which included a 5-year retrospective monthly calendar of childbearing, we suggest that migrants adapt quickly to an urban environment. Our results also reveal generational differences in recent and cumulative fertility. While migrants exhibit higher cumulative fertility than urban residents of the second and third generation, their fertility is significantly lower than rural averages in Ghana. Children of migrants exhibit childbearing patterns quite similar to those in higher-order generations. Most noteworthy is the nature of the disparities in childbearing patterns between migrants and the succeeding generations. Migrant women have higher lifetime fertility than urban natives. Migrant women also exhibit higher fertility over the last 5 years than second generation or high-order urban natives. But these first generation women exhibit lower fertility (vs. urban natives) for the year immediately prior to the survey. These patterns lend support to an interpretation that combines rather than opposes theories of selectivity, disruption, adaptation and socialization. We conclude by discussing mechanisms that might explain these interrelated processes of fertility adjustment and suggest that policies discouraging rural-urban migration need to be revisited.  相似文献   
998.
Cross-national differences in the association between origins and destinations correspond to differences in both welfare regime type and access to post-secondary education. Socialist and social democratic welfare regimes foster a weaker origin–destination association than liberal, corporatist, or mixed regimes do. Nations with better-educated labor forces tend to also be the nations where the association between origins and destinations is weakest. Furthermore, the social and educational policy interact so that the tendency for educational access to lower the origin–destination association is most pronounced in the liberal welfare setting where the association would otherwise be greatest. Greater access is not necessarily associated with greater equality of opportunity, and we find very weak evidence that equality of educational opportunity itself is a direct influence on equality of occupational opportunity (even though nations that have a strong origin–education association also have a strong origin–destination association).  相似文献   
999.
This study contributes to our understanding of the association between internal migration patterns and environmentally hazardous facilities, with a focus upon race-specific outmigration at the county-level, nationwide. Among research suggesting inequalities with regard to the social distribution of environmental risk, selective migration is often implied to be a key dynamic leading to differential exposure to proximate environmental hazards. Nonetheless, the models presented here provide no evidence of differential migratory response by race to environmentally hazardous facilities, net of a wide array of socioeconomic controls for labor force opportunity, climate, and demographic structure. Future research should consider these associations at more precise geographies and/or at the individual level.  相似文献   
1000.
Social Indicators Research - Objective: To explain the global quality of life (QOL) from 2000 indicators representing all aspects of life. Design and setting: Two cross sectional population...  相似文献   
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