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151.
152.
Ole Klungsøyr Joe Sexton Inger Sandanger Jan F. Nygård 《Journal of applied statistics》2013,40(4):843-861
A substantial degree of uncertainty exists surrounding the reconstruction of events based on memory recall. This form of measurement error affects the performance of structured interviews such as the Composite International Diagnostic Interview (CIDI), an important tool to assess mental health in the community. Measurement error probably explains the discrepancy in estimates between longitudinal studies with repeated assessments (the gold-standard), yielding approximately constant rates of depression, versus cross-sectional studies which often find increasing rates closer in time to the interview. Repeated assessments of current status (or recent history) are more reliable than reconstruction of a person's psychiatric history based on a single interview. In this paper, we demonstrate a method of estimating a time-varying measurement error distribution in the age of onset of an initial depressive episode, as diagnosed by the CIDI, based on an assumption regarding age-specific incidence rates. High-dimensional non-parametric estimation is achieved by the EM-algorithm with smoothing. The method is applied to data from a Norwegian mental health survey in 2000. The measurement error distribution changes dramatically from 1980 to 2000, with increasing variance and greater bias further away in time from the interview. Some influence of the measurement error on already published results is found. 相似文献
153.
Selecting an optimal 2k?pfractional factorial is structured as a mathematical programming problem. An algorithm is defined for the solution, and the case of additive costs is shown to have a known solution for resolution III designs. 相似文献
154.
陈爱华 《南京林业大学学报(人文社会科学版)》2009,9(4):55-62
青年卢卡奇对在所有修正主义著作中被奉为神明的方法论——自然科学的方法,即自然科学通过观察抽象实验等取得"纯"事实并找出它们的联系的方法,展开了批判性论述,揭示了自然科学的"纯"事实之伪;对当时盛行的实证主义和科学主义也进行了抨击;在此基础上提出了非常著名的思想——"自然是一个社会范畴"。这对于我们探究自然概念的社会本质、探索人与自然的伦理关系均有深刻的方法论意义。 相似文献
155.
Donald Black 《The British journal of sociology》2013,64(4):763-780
A value judgment says what is good or bad, and value‐free social science simply means social science free of value judgments. Yet many sociologists regard value‐free social science as undesirable or impossible and readily make value judgments in the name of sociology. Often they display confusion about such matters as the meaning of value‐free social science, value judgments internal and external to social science, value judgments as a subject of social science, the relevance of objectivity for value‐free social science, and the difference between the human significance of social science and value‐free social science. But why so many sociologists are so value‐involved – and generally so unscientific – is sociologically understandable: The closest and most distant subjects attract the least scientific ideas. And during the past century sociologists have become increasingly close to their human subject. The debate about value‐free social science is also part of an epistemological counterrevolution of humanists (including many sociologists) against the more scientific social scientists who invaded and threatened to expropriate the human subject during the past century. 相似文献
156.
It is well-known that the nonparametric maximum likelihood estimator (NPMLE) of a survival function may severely underestimate the survival probabilities at very early times for left truncated data. This problem might be overcome by instead computing a smoothed nonparametric estimator (SNE) via the EMS algorithm. The close connection between the SNE and the maximum penalized likelihood estimator is also established. Extensive Monte Carlo simulations demonstrate the superior performance of the SNE over that of the NPMLE, in terms of either bias or variance, even for moderately large Samples. The methodology is illustrated with an application to the Massachusetts Health Care Panel Study dataset to estimate the probability of being functionally independent for non-poor male and female groups rcspectively. 相似文献
157.
《Journal of Statistical Computation and Simulation》2012,82(1):171-185
In this paper, inference for the scale parameter of lifetime distribution of a k-unit parallel system is provided. Lifetime distribution of each unit of the system is assumed to be a member of a scale family of distributions. Maximum likelihood estimator (MLE) and confidence intervals for the scale parameter based on progressively Type-II censored sample are obtained. A β-expectation tolerance interval for the lifetime of the system is obtained. As a member of the scale family, half-logistic distribution is considered and the performance of the MLE, confidence intervals and tolerance intervals are studied using simulation. 相似文献
158.
S. Kalke 《Journal of Statistical Computation and Simulation》2013,83(4):641-667
In this paper, we introduce the p-generalized polar methods for the simulation of the p-generalized Gaussian distribution. On the basis of geometric measure representations, the well-known Box–Muller method and the Marsaglia–Bray rejecting polar method for the simulation of the Gaussian distribution are generalized to simulate the p-generalized Gaussian distribution, which fits much more flexibly to data than the Gaussian distribution and has already been applied in various fields of modern sciences. To prove the correctness of the p-generalized polar methods, we give stochastic representations, and to demonstrate their adequacy, we perform a comparison of six simulation techniques w.r.t. the goodness of fit and the complexity. The competing methods include adapted general methods and another special method. Furthermore, we prove stochastic representations for all the adapted methods. 相似文献
159.
This paper evaluates the ability of a Markov regime-switching log-normal (RSLN) model to capture the time-varying features of stock return and volatility. The model displays a better ability to depict a fat tail distribution as compared with using a log-normal model, which means that the RSLN model can describe observed market behavior better. Our major objective is to explore the capability of the model to capture stock market behavior over time. By analyzing the behavior of calibrated regime-switching parameters over different lengths of time intervals, the change-point concept is introduced and an algorithm is proposed for identifying the change-points in the series corresponding to the times when there are changes in parameter estimates. This algorithm for identifying change-points is tested on the Standard and Poor's 500 monthly index data from 1971 to 2008, and the Nikkei 225 monthly index data from 1984 to 2008. It is evident that the change-points we identify match the big events observed in the US stock market and the Japan stock market (e.g., the October 1987 stock market crash), and that the segmentations of stock index series, which are defined as the periods between change-points, match the observed bear–bull market phases. 相似文献
160.