全文获取类型
收费全文 | 2410篇 |
免费 | 66篇 |
国内免费 | 10篇 |
专业分类
管理学 | 177篇 |
民族学 | 5篇 |
人口学 | 14篇 |
丛书文集 | 75篇 |
理论方法论 | 25篇 |
综合类 | 579篇 |
社会学 | 103篇 |
统计学 | 1508篇 |
出版年
2024年 | 4篇 |
2023年 | 15篇 |
2022年 | 16篇 |
2021年 | 22篇 |
2020年 | 52篇 |
2019年 | 94篇 |
2018年 | 84篇 |
2017年 | 143篇 |
2016年 | 84篇 |
2015年 | 68篇 |
2014年 | 93篇 |
2013年 | 499篇 |
2012年 | 170篇 |
2011年 | 89篇 |
2010年 | 99篇 |
2009年 | 84篇 |
2008年 | 77篇 |
2007年 | 79篇 |
2006年 | 91篇 |
2005年 | 92篇 |
2004年 | 61篇 |
2003年 | 71篇 |
2002年 | 81篇 |
2001年 | 56篇 |
2000年 | 52篇 |
1999年 | 35篇 |
1998年 | 19篇 |
1997年 | 30篇 |
1996年 | 17篇 |
1995年 | 19篇 |
1994年 | 10篇 |
1993年 | 10篇 |
1992年 | 11篇 |
1991年 | 7篇 |
1990年 | 9篇 |
1989年 | 7篇 |
1988年 | 3篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 6篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有2486条查询结果,搜索用时 203 毫秒
141.
In this paper we present a perfect simulation method for obtaining perfect samples from collections of correlated Poisson random variables conditioned to be positive. We show how to use this method to produce a perfect sample from a Boolean model conditioned to cover a set of points: in W.S. Kendall and E. Thönnes (Pattern Recognition 32(9): 1569–1586, 1999), this special case was treated in a more complicated way. The method is applied to several simple examples where exact calculations can be made, so as to check correctness of the program using 2-tests, and some small-scale experiments are carried out to explore the behaviour of the conditioned Boolean model. 相似文献
142.
The hazard function plays an important role in reliability or survival studies since it describes the instantaneous risk of failure of items at a time point, given that they have not failed before. In some real life applications, abrupt changes in the hazard function are observed due to overhauls, major operations or specific maintenance activities. In such situations it is of interest to detect the location where such a change occurs and estimate the size of the change. In this paper we consider the problem of estimating a single change point in a piecewise constant hazard function when the observed variables are subject to random censoring. We suggest an estimation procedure that is based on certain structural properties and on least squares ideas. A simulation study is carried out to compare the performance of this estimator with two estimators available in the literature: an estimator based on a functional of the Nelson-Aalen estimator and a maximum likelihood estimator. The proposed least squares estimator tums out to be less biased than the other two estimators, but has a larger variance. We illustrate the estimation method on some real data sets. 相似文献
143.
Thomas Nittner 《Statistical Methods and Applications》2003,12(2):195-210
The additive model
is considered when some observations on x are missing at random but corresponding observations on y are available. Especially for this model, missing at random is an interesting case because the complete case analysis is expected to be no more suitable. A simulation experiment is reported and the different methods are compared based on their superiority with respect to the sample mean squared error. Some focus is also given on the sample variance and the estimated bias. In detail, the complete case analysis, a kind of stochastic mean imputation, a single imputation and the nearest neighbor imputation are discussed. 相似文献
144.
D. T. Mc Nichols 《统计学通讯:理论与方法》2013,42(6):2043-2062
Nonparametric maximum likelihood estimation of decreasing and unimodal density functions, based on observations subject to arbitrary right censorship, was considered by McNichols and Padgett(1982). In order to compute their estimators, however, nonlinear equations with linear constraints had to be maximized using numerical techniques. The exact solution to this problem can now be found. An example illustrates the simplicity of the method. 相似文献
145.
William F Roller 《统计学通讯:理论与方法》2013,42(9):2907-2920
A two-sample partially sequential probability ratio test (PSPRT) is considered for the two-sample location problem with one sample fixed and the other sequential. Observations are assumed to come from two normal poptilatlons with equal and known variances. Asymptotically in the fixed-sample size the PSPRT is a truncated Wald one sample sequential probability test. Brownian motion approximations for boundary-crossing probabilities and expected sequential sample size are obtained. These calculations are compared to values obtained by Monte Carlo simulation. 相似文献
146.
We obtain the rates of pointwise and uniform convergence of multivariate kernel density estimators using a random bandwidth vector obtained by some data-based algorithm. We are able to obtain faster rate for pointwise convergence. The uniform convergence rate is obtained under some moment condition on the marginal distribution. The rates are obtained under i.i.d. and strongly mixing type dependence assumptions. 相似文献
147.
The joint models for longitudinal data and time-to-event data have recently received numerous attention in clinical and epidemiologic studies. Our interest is in modeling the relationship between event time outcomes and internal time-dependent covariates. In practice, the longitudinal responses often show non linear and fluctuated curves. Therefore, the main aim of this paper is to use penalized splines with a truncated polynomial basis to parameterize the non linear longitudinal process. Then, the linear mixed-effects model is applied to subject-specific curves and to control the smoothing. The association between the dropout process and longitudinal outcomes is modeled through a proportional hazard model. Two types of baseline risk functions are considered, namely a Gompertz distribution and a piecewise constant model. The resulting models are referred to as penalized spline joint models; an extension of the standard joint models. The expectation conditional maximization (ECM) algorithm is applied to estimate the parameters in the proposed models. To validate the proposed algorithm, extensive simulation studies were implemented followed by a case study. In summary, the penalized spline joint models provide a new approach for joint models that have improved the existing standard joint models. 相似文献
148.
从经济分析的角度,作者分析了可持续发展过程中环境恶化的经济原因,即市场失灵和政府失灵;揭示出经济发展与环境保护之间存在的倒U型曲线的内在关系。 相似文献
149.
In this paper we provide new results about generalized ageing classes on the excess lifetime of a renewal process. We also obtain some characterizations of generalized ageing classes by means of the residual life at random time. 相似文献
150.
OLE F. CHRISTENSEN MORTEN FRYDENBERG JENS L. JENSEN JØRGEN G. PEDERSEN 《Scandinavian Journal of Statistics》2007,34(2):347-364
Abstract. The large deviation modified likelihood ratio statistic is studied for testing a variance component equal to a specified value. Formulas are presented in the general balanced case, whereas in the unbalanced case only the one-way random effects model is studied. Simulation studies are presented, showing that the normal approximation to the large deviation modified likelihood ratio statistic gives confidence intervals for variance components with coverage probabilities very close to the nominal confidence coefficient. 相似文献