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921.
This study examines whether changes in impulse control and sensation‐seeking across adolescence and early adulthood reflect independent or interdependent developmental processes. Data are drawn from a national longitudinal study (N = 8,270; 49% female; 33% Black, 22% Hispanic, 45% non‐Black, non‐Hispanic). An autoregressive latent trajectory model is used to test whether development in one trait influences development in the other. Although levels of these traits are inversely correlated, we do not find evidence that change over time in either trait is influenced by the prior level of the other. This failure to reject the null hypothesis is consistent with the view that sensation‐seeking and impulse control are the products of distinct neuropsychological systems that develop independently of one another.  相似文献   
922.
Urban growth is a major factor of global environmental change and has important impacts on biodiversity, such as changes in species composition and biotic homogenization. Most previous studies have focused on effects of urban area as a general measure of urbanization, and on few or single taxa. Here, we analyzed the impacts of the different components of urban sprawl (i.e., scattered and widespread urban growth) on species richness of a variety of taxonomic groups covering mosses, vascular plants, gastropods, butterflies, and birds at the habitat and landscape scales. Besides urban area, we considered the average age, imperviousness, and dispersion degree of urban area, along with human population density, to disentangle the effects of the different components of urban sprawl on biodiversity. The study was carried out in the Swiss Plateau that has undergone substantial urban sprawl in recent decades.Vascular plants and birds showed the strongest responses to urban sprawl, especially at the landscape scale, with non-native and ruderal plants proliferating and common generalist birds increasing at the expense of specialist birds as urban sprawl grew. Overall, urban area had the greatest contribution on such impacts, but additional effects of urban dispersion (i.e., increase of non-native plants) and human population density (i.e., increases of ruderal plants and common generalist birds) were found. Our findings support the hypothesis that negative impacts of urban sprawl on biodiversity can be reduced by compacting urban growth while still avoiding the formation of very densely populated areas.  相似文献   
923.
Novel approaches to natural resource management, particularly those which promote stakeholder participation, have been put forward as fundamental ingredients for establishing resilient, polycentric forms of environmental governance. This is nowhere more pertinent than in the case of the complex adaptive systems associated with urban areas. Decentralisation of urban green space management has been posited as an element thereof which, according to resilience thinking, should contribute to the adaptive capacity of cities and the ecosystem services upon which they rely. Implicit in this move towards increased adaptive capacity is the ability to manage through innovation. Although the importance of innovation towards system adaptability has been acknowledged, little work has thus far been carried out which demonstrates that innovative use of urban green space represents a form of adaptive response to environmental conditions. The current paper reports on research which maps examples of organised social-ecological innovation (OSEI) in an urban study area and evaluates them as adaptive responses to local environmental conditions which may contribute to system resilience. The results present OSEI as a coherent body of responses to local social and environmental deprivation, exhibiting diversity and adaptability according to individual contexts. The study therefore provides evidence for the importance of local stakeholder-led innovation as in the building of adaptive capacity in urban social-ecological systems.  相似文献   
924.
This paper uses longitudinal data from the Philippines to analyze determinants of children’s time allocation. The estimation method takes into account both the simultaneity of time use decisions, by allowing for correlation of residuals across time uses, and unobservable family heterogeneity, through the inclusion of household fixed effects. Importantly, this improved estimation method leads to different results than when applying the methods previously used in the literature. Girls suffer significantly from the absence of their mother with a reduction in time spent in school that is equivalent to dropping out completely. This effect is substantially larger when controlling for household unobservables than when not. Boys increase time spent working on market related activities in response to an absent father, although this time appears to come out of leisure rather than school or doing household chores. Land ownership substantially increase the time boys spend on school activities, whereas renting land reduces the time girls spend on school. Finally, there does not appear to be a substantial trade-off between time spent on school and work, either in the market or at home.  相似文献   
925.
Each year, thousands of children who cross international borders are destined for homes with adoptive families. For most, this journey from their homeland brings them to loving new homes where they will thrive and prosper. For others, the journey is hazardous and the destination uncertain.  相似文献   
926.
Attempts to control the importation of infectious diseases through the medical screening and evaluation of immigrants and refugees represent the modern application of some of the earliest recorded public health interventions.
States with long-standing immigration programmes continue to require the medical examination and screening of migrants for certain diseases. In some instances, the public health effectiveness of these immigration medical assessments is of questionable value when considered from a population health basis.
This article reviews current practices and describes recent studies where more modern and epidemiologically based immigration medical interventions have been undertaken. A more effective immigration medical assessment process is proposed through the use of results of this more empirical approach to immigration medical screening.  相似文献   
927.
928.
The Rate of Return on Investment in Wine   总被引:1,自引:0,他引:1  
Is wine an investment alternative to stocks and bonds? First, we review prior studies regarding the pecuniary rate of return to wine and other alternatives to financial assets. Next, we calculate the rate of return to holding red Bordeaux wine from 1986 to 1996 using a repeat‐sale regression. Finally, we contrast the financial performance of wine, both on an aggregate basis and for various portfolios, to that of other asset classes. We conclude that wine does not yield greater returns than financial assets, especially when the volatility of returns and transaction costs are taken into account.  相似文献   
929.
930.
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