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101.
A number of methods of obtaining the distribution of the optimum of the ‘wait and see’ stochastic programming model have been proposed, but computational experience for these is currently limited to the solution of small problems. The purpose of this paper is to discuss the role of the ‘wait and see’ model in planning, and to propose a method of analysis based on the minimax and maximax decision criteria. The approach requires the solution of a special class of non-linear programming problems. Computational results to date suggest that it will be possible to analyse practically sized problems in this way.  相似文献   
102.
The Color Additives Scientific Review Panel considered whether there was information sufficient to perform a carcinogenic risk assessment on the colors D&C Red No. 19 (R-19), D&C Red No. 37 (R-37), D&C Orange No. 17 (O-17), D&C Red No. 9 (R-9), D&C Red No. 8 (R-8) and FD&C Red No. 3 (R-3) and to evaluate the assessments sent to FDA as part of the petitions for use of the colors for drug and external uses by the Cosmetic, Toiletry and Fragrance Association (CTFA). There is a lack of human data concerning the colors for making a human health assessment, so the assessments are based upon the extrapolation of animal data. The risk assessments are determined for exposure to single chemicals. Excluded from consideration are possible effects from exposure to multiple chemicals, such as co-carcinogenesis, promotion, synergism, antagonism, etc. In the light of recent efforts in establishing a consensus in risk assessment, the Panel has determined that the CTFA assessments for R-10, O-17, and R-9 are consistent with present acceptable usages, although it questions some of the assumptions used in the assessments. The Panel identified a number of general assumptions made, and discusses their validity, their impact on total uncertainty, and the potential options to address the gaps in understanding that necessitate the assumption. The Panel also derived revised risk estimates using more "reasonable" assumptions than "worst-case" situations, for 90th percentile and average exposure. For those assumptions that are easily quantifiable, the Panel's estimates are less than an order of magnitude lower than the CTFA risk estimates, indicating that the underestimates and overestimates of the CTFA risk estimates tend to balance each other. The impact of most of the assumptions is not quantifiable. The assessment for R-3 is complicated by the fact that there is no good skin penetrance study for this color. It was assumed that the penetrance is similar to that of another water-soluble xanthene color, R-19. It is expected that the absorption of the color is not likely to exceed that of the smaller molecule, R-19. Therefore, the risk estimates are similar to the CTFA estimates, but with different reasoning. The estimates for R-8 and R-37 are different from the others in that there is a lack of any exposure or toxicological information on these colors.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
103.
Borjas GJ 《Demography》2001,38(3):357-361
In my original study, "Long-Run Convergence of Ethnic Skill Differentials," I concluded that the ethnic differentials introduced by the Great Migration seemed to persist into the second and third generations. Alba, Lutz, and Vesselinov argue that my study contained a number of conceptual and data problems, and conclude that the correlation between the skills of the first and the third generations disappears when these problems are taken into account. My reanalysis of the Alba et al. data, however, documents a stronger link between the skills of the first and the third generations than suggested by those authors.  相似文献   
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Making a career switch from clinical practice to medical management requires preparation and planning. There are numerous steps you can take to smooth out the transition. Most importantly, you must find ways to gain valuable leadership and management experiences before you can expect to land a good medical management position. Discover ways to cultivate that experience through staff posts, part-time positions or volunteer work.  相似文献   
107.
Job burnout for workers in any career can be frightening. It's truly debilitating to think that your job and career are worthless, that your future isn't bright. There are, however, some steps you can take to recognize, avoid or overcome the stress and anxiety that leads to job burnout.  相似文献   
108.
Making patient safety the No. 1 priority at a hospital or clinic sounds like a easy task. It isn't. At one Oklahoma health system, an improved patient safety program is a massive effort requiring input and participation from every member of the staff. Figuring out how to convince employees that patient safety is their first priority means developing an extensive communication and education program.  相似文献   
109.
Volunteer work and well-being   总被引:2,自引:0,他引:2  
Using two waves of panel data from Americans' Changing Lives (House 1995) (N = 2,681), we examine the relationships between volunteer work in the community and six aspects of personal well-being: happiness, life satisfaction, self-esteem, sense of control over life, physical health, and depression. Prior research has more often examined the effects of voluntary memberships than of volunteer work, has used cross-sectional rather than longitudinal data, and, when longitudinal, has emphasized social causation over selection effects. Focusing only on the consequences of volunteer work overlooks the antecedents of human agency. People with greater personality resources and better physical and mental health should be more likely to seek (or to be sought for) community service. Hence, we examine both selection and social causation effects. Results show that volunteer work indeed enhances all six aspects of well-being and, conversely, people who have greater well-being invest more hours in volunteer service. Given this, further understanding of self- versus social-selection processes seems an important next step. Do positive, healthy people actively seek out volunteer opportunities, or do organizations actively recruit individuals of these types (or both)? Explaining how positive consequences flow from volunteer service may offer a useful counterpoint to stress theory, which has focused primarily on negative life experiences and their sequelae.  相似文献   
110.
Neighborhood disadvantage, stress, and drug use among adults   总被引:1,自引:0,他引:1  
This paper explores the relationships among neighborhood disadvantage, stress, and the likelihood of drug use in a sample of adults (N = 1,101). Using the 1995 Detroit Area Study in conjunction with tract-level data from the 1990 census, we find a positive relationship between neighborhood disadvantage and drug use, and this relationship remains statistically significant net of controls for individual-level socioeconomic status. Neighborhood disadvantage is moderately associated with drug related behaviors, indirectly through increased social stressors and higher levels of psychological distress among residents of disadvantaged neighborhoods. A residual effect of neighborhood disadvantage remains, net of a large number of socially relevant controls. Finally, results from interactive models suggest that the relationship between neighborhood disadvantage and drug use is most pronounced among individuals with lower incomes.  相似文献   
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