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251.
The paper applies classical statistical principles to yield new tools for risk assessment and makes new use of epidemiological data for human risk assessment. An extensive clinical and epidemiological study of workers engaged in the manufacturing and formulation of aldrin and dieldrin provides occupational hygiene and biological monitoring data on individual exposures over the years of employment and provides unusually accurate measures of individual lifetime average daily doses. In the cancer dose-response modeling, each worker is treated as a separate experimental unit with his own unique dose. Maximum likelihood estimates of added cancer risk are calculated for multistage, multistage-Weibull, and proportional hazards models. Distributional characterizations of added cancer risk are based on bootstrap and relative likelihood techniques. The cancer mortality data on these male workers suggest that low-dose exposures to aldrin and dieldrin do not significantly increase human cancer risk and may even decrease the human hazard rate for all types of cancer combined at low doses (e.g., 1 g/kg/day). The apparent hormetic effect in the best fitting dose-response models for this data set is statistically significant. The decrease in cancer risk at low doses of aldrin and dieldrin is in sharp contrast to the U.S. Environmental Protection Agency's upper bound on cancer potency based on mouse liver tumors. The EPA's upper bound implies that lifetime average daily doses of 0.0000625 and 0.00625 g/kg body weight/day would correspond to increased cancer risks of 0.000001 and 0.0001, respectively. However, the best estimate from the Pernis epidemiological data is that there is no increase in cancer risk in these workers at these doses or even at doses as large as 2 g/kg/day.  相似文献   
252.
This Internet research project examined the relationship between consumption of muscle and fitness magazines and/or various indices of pornography and body satisfaction in gay and heterosexual men. Participants (N = 101) were asked to complete body satisfaction questionnaires that addressed maladaptive eating attitudes, the drive for muscularity, and social physique anxiety. Participants also completed scales measuring self-esteem, depression, and socially desirable responding. Finally, respondents were asked about their consumption of muscle and fitness magazines and pornography. Results indicated that viewing and purchasing of muscle and fitness magazines correlated positively with levels of body dissatisfaction for both gay and heterosexual men. Pornography exposure was positively correlated with social physique anxiety for gay men. The limitations of this study and directions for future research are outlined.  相似文献   
253.
The informal economy has developed in sociological theory to refer to clusters of illegal or quasi-illegal activities, usually unreported, by which people in some immigrant or ethnic communities earn income outside regular businesses and jobs. This article first extrapolates a set of characteristics beyond the legal status of such activities that define the informal economy. These provide a richer framework for future research and the basis for identifying informal economic activity in other sectors of the legitimate mainstream economy. In fact, informalization seems to have gone from marginal activities to a mainstream movement to make large sectors more fluid, network-based, and less regulated—the informalized economy. Its characteristics are identified. They overlap with the first set but differ principally in terms of extending Merton's proposition that different social structures exert different pressures to engage in non-conforming behavior. The article concludes with policy implications for fostering greater entrepreneurship in marginal migrant communities, and it suggests new ways for economic sociologists to study network transactions in modern corporations of informal economic activity through generative sociology.  相似文献   
254.
Little is known about the characteristics of adolescent sex offenders who do not reoffend. Most studies emphasize reoffense rates, recidivism and those who reoffend. Moreover, these studies provide quantitative summaries without describing the individual, his behavior, and challenges after treatment. The present study seeks to provide novel information about the life experiences of adolescent sex offenders who have not reoffended after reentering society. Through a structured questionnaire and an in-depth qualitative interview, the adolescents (N = 7) provided information regarding their life experiences after treatment with an emphasis on the challenges they face in society.  相似文献   
255.
A prominent hospital in Pennsylvania turned to CPOE to help reduce medical errors and improve patient care. Learn what steps hospital officials took to establish a successful CPOE system.  相似文献   
256.
This paper discusses how fishing communities around the world avoid destructive overfishing through local and largely informal self-management. The paper offers many examples that undermine the widespread assumption that the tragedy of the commons is inevitable without government regulation.  相似文献   
257.
This paper considers the problem of choosing the number of bootstrap repetitions B for bootstrap standard errors, confidence intervals, confidence regions, hypothesis tests, p‐values, and bias correction. For each of these problems, the paper provides a three‐step method for choosing B to achieve a desired level of accuracy. Accuracy is measured by the percentage deviation of the bootstrap standard error estimate, confidence interval length, test's critical value, test's p‐value, or bias‐corrected estimate based on B bootstrap simulations from the corresponding ideal bootstrap quantities for which B=. The results apply quite generally to parametric, semiparametric, and nonparametric models with independent and dependent data. The results apply to the standard nonparametric iid bootstrap, moving block bootstraps for time series data, parametric and semiparametric bootstraps, and bootstraps for regression models based on bootstrapping residuals. Monte Carlo simulations show that the proposed methods work very well.  相似文献   
258.
A new class of generalized correlation coefficients that contains the Pearson and Kendall statistics as special cases was defined by Chinchilli et al. (2005) and applied to the estimation of correlations coefficients within the context of 2×2 cross-over designs for clinical trials. In this paper, we determine the infinitesimal robustness and local stability properties of these generalized correlation coefficients by deriving their corresponding influence functions. For cases in which the population distribution is a bivariate normal or a mixture of bivariate normal distributions we obtain explicit formulas, and establish monotonicity and sign-reverse rule properties of the generalized correlation coefficients.  相似文献   
259.
260.
Methods are proposed for testing stochastic dominance of any pre–specified order, with primary interest in the distributions of income. We consider consistent tests, that are similar to Kolmogorov–Smirnov tests, of the complete set of restrictions that relate to the various forms of stochastic dominance. For such tests, in the case of tests for stochastic dominance beyond first order, we propose and justify a variety of approaches to inference based on simulation and the bootstrap. We compare these approaches to one another and to alternative approaches based on multiple comparisons in the context of a Monte Carlo experiment and an empirical example.  相似文献   
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