全文获取类型
收费全文 | 11981篇 |
免费 | 189篇 |
国内免费 | 1篇 |
专业分类
管理学 | 1474篇 |
民族学 | 54篇 |
人才学 | 3篇 |
人口学 | 1089篇 |
丛书文集 | 57篇 |
理论方法论 | 1026篇 |
综合类 | 103篇 |
社会学 | 5633篇 |
统计学 | 2732篇 |
出版年
2023年 | 58篇 |
2022年 | 65篇 |
2021年 | 64篇 |
2020年 | 174篇 |
2019年 | 218篇 |
2018年 | 324篇 |
2017年 | 433篇 |
2016年 | 278篇 |
2015年 | 235篇 |
2014年 | 287篇 |
2013年 | 2208篇 |
2012年 | 417篇 |
2011年 | 315篇 |
2010年 | 289篇 |
2009年 | 211篇 |
2008年 | 253篇 |
2007年 | 255篇 |
2006年 | 261篇 |
2005年 | 246篇 |
2004年 | 194篇 |
2003年 | 207篇 |
2002年 | 216篇 |
2001年 | 321篇 |
2000年 | 288篇 |
1999年 | 269篇 |
1998年 | 204篇 |
1997年 | 169篇 |
1996年 | 219篇 |
1995年 | 189篇 |
1994年 | 199篇 |
1993年 | 168篇 |
1992年 | 201篇 |
1991年 | 213篇 |
1990年 | 196篇 |
1989年 | 170篇 |
1988年 | 193篇 |
1987年 | 179篇 |
1986年 | 141篇 |
1985年 | 176篇 |
1984年 | 180篇 |
1983年 | 156篇 |
1982年 | 122篇 |
1981年 | 97篇 |
1980年 | 97篇 |
1979年 | 121篇 |
1978年 | 93篇 |
1977年 | 81篇 |
1975年 | 63篇 |
1974年 | 67篇 |
1973年 | 60篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Chain sampling plan for variables inspection 总被引:1,自引:0,他引:1
SUMMARY This paper extends the concept of chain sampling to variables inspection when the standard deviation of the normally distributed characteristic is known. A discussion of the shape of the known sigma single-sampling variables plan is given. The chain sampling plan for variables inspection will be useful when testing is costly or destructive. 相似文献
992.
In this paper, a new tightening concept has been incorporated into the single-level continuous sampling plan CSP-1, such that quality degradation will warrant sampling inspection to cease beyond a certain number of sampled items, until new evidence of good quality is established. The expressions of the performance measures for this new plan, such as the operating characteristic, average outgoing quality and average fraction inspected, are derived using a Markov chain model. The advantage of the tightened CSP-1 plan is that it is possible to lower the average outgoing quality limit. 相似文献
993.
A two-point estimator is proposed for the proportion of studies with positive trends among a collection of studies, some of which may demonstrate negative trends. The proposed estimator is the y-intercept of the secant line joining the points (a, F?(a)) and (b, F?(b)), where F?(p) is the empirical distribution function of p-values from one-tailed tests for positive trend derived from the individual studies. Although this estimator is negatively biased for any choice of the points 0 ≤ a < b ≤ 1, the bias is less than that of the previously proposed one-point estimator defined by setting b = 1. The bias of the two-point estimator is smallest when a and b approach the inflection point of the true distribution function, E [F?(p)]. The utility of the two-point estimator is demonstrated by using it to estimate the number of male-mouse liver carcinogens among carcinogenicity studies conducted by the National Toxicology Program. 相似文献
994.
Raymond J. Carroll Laurence S. Freedman Victor Kipnis Li Li 《Revue canadienne de statistique》1998,26(3):467-477
Measurement-error modelling occurs when one cannot observe a covariate, but instead has possibly replicated surrogate versions of this covariate measured with error. The vast majority of the literature in measurement-error modelling assumes (typically with good reason) that given the value of the true but unobserved (latent) covariate, the replicated surrogates are unbiased for latent covariate and conditionally independent. In the area of nutritional epidemiology, there is some evidence from biomarker studies that this simple conditional independence model may break down due to two causes: (a) systematic biases depending on a person's body mass index, and (b) an additional random component of bias, so that the error structure is the same as a one-way random-effects model. We investigate this problem in the context of (1) estimating distribution of usual nutrient intake, (2) estimating the correlation between a nutrient instrument and usual nutrient intake, and (3) estimating the true relative risk from an estimated relative risk using the error-prone covariate. While systematic bias due to body mass index appears to have little effect, the additional random effect in the variance structure is shown to have a potentially important effect on overall results, both on corrections for relative risk estimates and in estimating the distribution of usual nutrient intake. However, the effect of dietary measurement error on both factors is shown via examples to depend strongly on the data set being used. Indeed, one of our data sets suggests that dietary measurement error may be masking a strong risk of fat on breast cancer, while for a second data set this masking is not so clear. Until further understanding of dietary measurement is available, measurement-error corrections must be done on a study-specific basis, sensitivity analyses should be conducted, and even then results of nutritional epidemiology studies relating diet to disease risk should be interpreted cautiously. 相似文献
995.
S. P. Brooks 《Statistics and Computing》1998,8(3):267-274
Yu (1995) provides a novel convergence diagnostic for Markov chain Monte Carlo (MCMC) which provides a qualitative measure of mixing for Markov chains via a cusum path plot for univariate parameters of interest. The method is based upon the output of a single replication of an MCMC sampler and is therefore widely applicable and simple to use. One criticism of the method is that it is subjective in its interpretation, since it is based upon a graphical comparison of two cusum path plots. In this paper, we develop a quantitative measure of smoothness which we can associate with any given cusum path, and show how we can use this measure to obtain a quantitative measure of mixing. In particular, we derive the large sample distribution of this smoothness measure, so that objective inference is possible. In addition, we show how this quantitative measure may also be used to provide an estimate of the burn-in length for any given sampler. We discuss the utility of this quantitative approach, and highlight a problem which may occur if the chain is able to remain in any one state for some period of time. We provide a more general implementation of the method to overcome the problem in such cases. 相似文献
996.
M.S. Ahmed 《Australian & New Zealand Journal of Statistics》1998,40(3):373-376
Kiregyera (1984), Mukerjee, Rao & Vijayan (1987), and Tripathi & Ahmed (1995) considered a number of regression-type estimators where information on two auxiliary variables related to study variable is available at different levels. Mukerjee et al . (1987) suggested three estimators and computed their mean square errors, but the computations seem to be incorrect. This note corrects them, and finds their estimators are no better than that of Kiregyera (1984). The estimator suggested by Tripathi & Ahmed (1995) is the best in the sense of having the smallest mean square error. 相似文献
997.
Smoothing parameter selection in nonparametric regression using an improved Akaike information criterion 总被引:1,自引:0,他引:1
Clifford M. Hurvich Jeffrey S. Simonoff & Chih-Ling Tsai 《Journal of the Royal Statistical Society. Series B, Statistical methodology》1998,60(2):271-293
Many different methods have been proposed to construct nonparametric estimates of a smooth regression function, including local polynomial, (convolution) kernel and smoothing spline estimators. Each of these estimators uses a smoothing parameter to control the amount of smoothing performed on a given data set. In this paper an improved version of a criterion based on the Akaike information criterion (AIC), termed AICC , is derived and examined as a way to choose the smoothing parameter. Unlike plug-in methods, AICC can be used to choose smoothing parameters for any linear smoother, including local quadratic and smoothing spline estimators. The use of AICC avoids the large variability and tendency to undersmooth (compared with the actual minimizer of average squared error) seen when other 'classical' approaches (such as generalized cross-validation (GCV) or the AIC) are used to choose the smoothing parameter. Monte Carlo simulations demonstrate that the AICC -based smoothing parameter is competitive with a plug-in method (assuming that one exists) when the plug-in method works well but also performs well when the plug-in approach fails or is unavailable. 相似文献
998.
S. Eguchi & J. Copas 《Journal of the Royal Statistical Society. Series B, Statistical methodology》1998,60(4):709-724
The local maximum likelihood estimate θ^ t of a parameter in a statistical model f ( x , θ) is defined by maximizing a weighted version of the likelihood function which gives more weight to observations in the neighbourhood of t . The paper studies the sense in which f ( t , θ^ t ) is closer to the true distribution g ( t ) than the usual estimate f ( t , θ^) is. Asymptotic results are presented for the case in which the model misspecification becomes vanishingly small as the sample size tends to ∞. In this setting, the relative entropy risk of the local method is better than that of maximum likelihood. The form of optimum weights for the local likelihood is obtained and illustrated for the normal distribution. 相似文献
999.
S. Gurler 《Statistical Papers》2012,53(1):23-31
Sequential order statistics is an extension of ordinary order statistics. They model the successive failure times in sequential k-out-of-n systems, where the failures of components possibly affect the residual lifetimes of the remaining ones. In this paper, we consider the residual lifetime of the components after the kth failure in the sequential (n − k + 1)-out-of-n system. We extend some results on the joint distribution of the residual lifetimes of the remaining components in an ordinary (n − k + 1)-out-of-n system presented in Bairamov and Arnold (Stat Probab Lett 78(8):945–952, 2008) to the case of the sequential (n − k + 1)-out-of-n system. 相似文献
1000.
Differences between plant varieties are based on phenotypic observations, which are both space and time consuming. Moreover, the phenotypic data result from the combined effects of genotype and environment. On the contrary, molecular data are easier to obtain and give a direct access to the genotype. In order to save experimental trials and to concentrate efforts on the relevant comparisons between varieties, the relationship between phenotypic and genetic distances is studied. It appears that the classical genetic distances based on molecular data are not appropriate for predicting phenotypic distances. In the linear model framework, we define a new pseudo genetic distance, which is a prediction of the phenotypic one. The distribution of this distance given the pseudo genetic distance is established. Statistical properties of the predicted distance are derived when the parameters of the model are either given or estimated. We finally apply these results to distinguishing between 144 maize lines. This case study is very satisfactory because the use of anonymous molecular markers (RFLP) leads to saving 29% of the trials with an acceptable error risk. These results need to be confirmed on other varieties and species and would certainly be improved by using genes coding for phenotypic traits. 相似文献