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941.
Research in the area of bandwidth selection was an active topic in the 1980s and 1990s, however, recently there has been little research in the area. We re-opened this investigation and have found a new method for estimating mean integrated squared error for kernel density estimators. We provide an overview of other methods to obtain optimal bandwidths and offer a comparison of these methods via a simulation study. In certain situations, our method of estimating an optimal bandwidth yields a smaller MISE than competing methods to compute bandwidths. This procedure is illustrated by an application to two data sets. 相似文献
942.
Lovie J. Jackson Catherine Roller White† Kirk O'Brien† Paul DiLorenzo† Ernie Cathcart† Mary Wolf† Delilah Bruskas‡ Peter J. Pecora† § Vivian Nix-Early¶ Jorge Cabrera† 《Child & Family Social Work》2010,15(1):107-117
This study examined spiritual coping mechanisms, beliefs about spirituality and participation in spiritual activities and in other positive activities among adolescents in foster care. A multidimensional measure of spirituality was developed for face-to-face interviews with 188 youth (ages 14–17) from diverse racial/ethnic backgrounds in the United States. Findings revealed 95% of youth believe in God, over 70% believe God is 'creator' and God is 'love', and 79% considered prayer a spiritual practice. Most youth said love and forgiveness help them heal. Two-thirds (67%) reported responding to 'bad or tragic things happening' by spending time alone, and over half responded by praying (59%) or sharing the problem with someone else (56%). Youth's top three spiritual goals were to follow God's plan for them, become a better person, and know their purpose in life. Based on the value youth ascribed to spiritual coping mechanisms, recommendations for policy and practice focus on the integration of spirituality into practice and caregiving for youth in foster care. 相似文献
943.
Sujit K. Sahu Alan E. Gelfand David M. Holland 《Journal of the Royal Statistical Society. Series C, Applied statistics》2010,59(1):77-103
Summary. Motivated by the problem of predicting chemical deposition in eastern USA at weekly, seasonal and annual scales, the paper develops a framework for joint modelling of point- and grid-referenced spatiotemporal data in this context. The hierarchical model proposed can provide accurate spatial interpolation and temporal aggregation by combining information from observed point-referenced monitoring data and gridded output from a numerical simulation model known as the 'community multi-scale air quality model'. The technique avoids the change-of-support problem which arises in other hierarchical models for data fusion settings to combine point- and grid-referenced data. The hierarchical space–time model is fitted to weekly wet sulphate and nitrate deposition data over eastern USA. The model is validated with set-aside data from a number of monitoring sites. Predictive Bayesian methods are developed and illustrated for inference on aggregated summaries such as quarterly and annual sulphate and nitrate deposition maps. The highest wet sulphate deposition occurs near major emissions sources such as fossil-fuelled power plants whereas lower values occur near background monitoring sites. 相似文献
944.
Causal inference approaches in systems genetics exploit quantitative trait loci (QTL) genotypes to infer causal relationships among phenotypes. The genetic architecture of each phenotype may be complex, and poorly estimated genetic architectures may compromise the inference of causal relationships among phenotypes. Existing methods assume QTLs are known or inferred without regard to the phenotype network structure. In this paper we develop a QTL-driven phenotype network method (QTLnet) to jointly infer a causal phenotype network and associated genetic architecture for sets of correlated phenotypes. Randomization of alleles during meiosis and the unidirectional influence of genotype on phenotype allow the inference of QTLs causal to phenotypes. Causal relationships among phenotypes can be inferred using these QTL nodes, enabling us to distinguish among phenotype networks that would otherwise be distribution equivalent. We jointly model phenotypes and QTLs using homogeneous conditional Gaussian regression models, and we derive a graphical criterion for distribution equivalence. We validate the QTLnet approach in a simulation study. Finally, we illustrate with simulated data and a real example how QTLnet can be used to infer both direct and indirect effects of QTLs and phenotypes that co-map to a genomic region. 相似文献
945.
Scott Alan Carson 《The Social Science Journal》2011,48(1):234-249
Using a source of 19th century Texas state prison inmate records, the present study contrasts the biological living conditions of comparable 19th century African and European Americans. Average Black stature ironically increased during the antebellum period and decreased immediately after emancipation, while average White stature declined throughout the second half of the 19th century. Texas Black BMI values declined during the late 19th and early 20th centuries; however, White BMI values increased, indicating considerable 19th century biological inequality by race. Therefore, the known material inequality that existed in the 19th century American South is reinforced with biological markers. 相似文献
946.
947.
Leanne E. Atwater Shelley D. Dionne Bruce Avolio John F. Camobreco Alan W. Lau 《Human Relations》1999,52(12):1543-1562
This study tracked the leadership development of236 male cadets from matriculation through graduation ata military college. Cognitive ability, physical fitness,prior influence experiences, and self-esteem measured in Year 1 were relevant to predictingthose who assumed formal leadership positions in Year 4.Physical fitness and prior influence experiencesmeasured when cadets entered the college predicted leader effectiveness rated in their fourthyear. Stress tolerance and moral reasoning levels didnot predict leader emergence or effectiveness, thoughthe set of individual difference measures significantly predicted emergence and effectiveness. Physicalfitness levels and moral reasoning increased over timefor all cadets, though surprisingly, levels ofself-esteem and stress tolerance did not increase over time. Overall the study demonstrated thatleadership effectiveness and emergence could bepredicted from early measures of individualdifferences. 相似文献
948.
David Griffith Rachata Muneepeerakul Genevieve Guerry Alvaro Carmona Cabrero Jeffrey C. Johnson Rafael Munoz-Carpena Michael Puma Upmanu Lall Mehran Homayounfar 《International migration (Geneva, Switzerland)》2023,61(5):186-200
Research on migration has become more challenging due to at least four factors: (1) more complex migration traditions; (2) the development of migration economies that engage many types of migrants from ever more social and cultural backgrounds; (3) increasing likelihood of climate change-driven environmental migration; and (4) increasing likelihood of conflict-based migration in some contexts. These developments have shaken economic theories of migration and have encouraged interdisciplinary, methodologically mixed, qualitative and quantitative research and analysis. From a review of the literature, we have gleaned 11 common themes about environmental, economic and conflict migration that we differentiate by process (migration behaviours that are still evolving) and patterns (migration behaviours that have become customary). We then consider how positive and negative dimensions of migration can be captured and represented with close attention to livelihood constellations (multiple economic activities combined by individuals, households and families). Finally, focusing on Somalia and agro-pastoral peoples generally, where recent environmental and conflict migration have been added to decades of economic migration and centuries of seasonal, environmental migration associated with pastoralism, we combine historical and qualitative work to demonstrate the value of a livelihood constellation perspective. 相似文献
949.
We consider the choice of union membership in the UK and its effect on the union/non‐union wage differential allowing for the endogeneity of the union choice. We include identifying variables not previously used and find that correcting for selectivity is important and has a large impact on the estimated differential. Moreover, union choice is itself affected by the wage gap. 相似文献
950.