全文获取类型
收费全文 | 16436篇 |
免费 | 508篇 |
国内免费 | 200篇 |
专业分类
管理学 | 1580篇 |
劳动科学 | 2篇 |
民族学 | 122篇 |
人才学 | 1篇 |
人口学 | 414篇 |
丛书文集 | 1015篇 |
理论方法论 | 534篇 |
综合类 | 8786篇 |
社会学 | 1212篇 |
统计学 | 3478篇 |
出版年
2024年 | 23篇 |
2023年 | 149篇 |
2022年 | 148篇 |
2021年 | 195篇 |
2020年 | 326篇 |
2019年 | 377篇 |
2018年 | 427篇 |
2017年 | 541篇 |
2016年 | 470篇 |
2015年 | 527篇 |
2014年 | 865篇 |
2013年 | 1894篇 |
2012年 | 1166篇 |
2011年 | 1102篇 |
2010年 | 894篇 |
2009年 | 835篇 |
2008年 | 938篇 |
2007年 | 1026篇 |
2006年 | 958篇 |
2005年 | 837篇 |
2004年 | 727篇 |
2003年 | 615篇 |
2002年 | 508篇 |
2001年 | 374篇 |
2000年 | 280篇 |
1999年 | 168篇 |
1998年 | 93篇 |
1997年 | 100篇 |
1996年 | 89篇 |
1995年 | 79篇 |
1994年 | 65篇 |
1993年 | 57篇 |
1992年 | 51篇 |
1991年 | 27篇 |
1990年 | 34篇 |
1989年 | 36篇 |
1988年 | 26篇 |
1987年 | 25篇 |
1986年 | 25篇 |
1985年 | 15篇 |
1984年 | 16篇 |
1983年 | 10篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1975年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
91.
P. R. Rosenbaum 《Journal of the Royal Statistical Society. Series C, Applied statistics》1999,48(1):63-78
In two observational studies, one investigating the effects of minimum wage laws on employment and the other of the effects of exposures to lead, an estimated treatment effect's sensitivity to hidden bias is examined. The estimate uses the combined quantile averages that were introduced in 1981 by B. M. Brown as simple, efficient, robust estimates of location admitting both exact and approximate confidence intervals and significance tests. Closely related to Gastwirth's estimate and Tukey's trimean, the combined quantile average has asymptotic efficiency for normal data that is comparable with that of a 15% trimmed mean, and higher efficiency than the trimean, but it has resistance to extreme observations or breakdown comparable with that of the trimean and better than the 15% trimmed mean. Combined quantile averages provide consistent estimates of an additive treatment effect in a matched randomized experiment. Sensitivity analyses are discussed for combined quantile averages when used in a matched observational study in which treatments are not randomly assigned. In a sensitivity analysis in an observational study, subjects are assumed to differ with respect to an unobserved covariate that was not adequately controlled by the matching, so that treatments are assigned within pairs with probabilities that are unequal and unknown. The sensitivity analysis proposed here uses significance levels, point estimates and confidence intervals based on combined quantile averages and examines how these inferences change under a range of assumptions about biases due to an unobserved covariate. The procedures are applied in the studies of minimum wage laws and exposures to lead. The first example is also used to illustrate sensitivity analysis with an instrumental variable. 相似文献
92.
P. J. Avery & D. A. Henderson 《Journal of the Royal Statistical Society. Series C, Applied statistics》1999,48(4):489-503
Non-coding deoxyribonucleic acid (DNA) can typically be modelled by a sequence of Bernoulli random variables by coding one base, e.g. T, as 1 and other bases as 0. If a segment of a sequence is functionally important, the probability of a 1 will be different in this changed segment from that in the surrounding DNA. It is important to be able to see whether such a segment occurs in a particular DNA sequence and to pin-point it so that a molecular biologist can investigate its possible function. Here we discuss methods for testing the occurrence of such a changed segment and how to estimate the end points of it. Maximum-likelihood-based methods are not very tractable and so a nonparametric method based on the approach of Pettitt has been developed. The problem and its solution are illustrated by a specific DNA example. 相似文献
93.
Some general remarks are made about likelihood factorizations, distinguishing parameter-based factorizations and concentration-graph factorizations. Two parametric families of distributions for mixed discrete and continuous variables are discussed. Conditions on graphs are given for the circumstances under which their joint analysis can be split into separate analyses, each involving a reduced set of component variables and parameters. The result shows marked differences between the two families although both involve the same necessary condition on prime graphs. This condition is both necessary and sufficient for simplified estimation in Gaussian and for discrete log linear models. 相似文献
94.
Laurent Bordes 《Scandinavian Journal of Statistics》1999,26(3):345-361
In this paper we investigate the asymptotic properties of estimators obtained for the semiparametric additive accelerated life model proposed by Bagdonavicius & Nikulin (1995). This model generalizes the well known additive hazards model of survival analysis and is close to the general transformation model (see Dabrowska & Doksum, 1988). Asymptotic properties of the estimator of the regression parameter and the estimator of the reliability function are given in the case of right censoring for discretized data and a numerical example illustrates these results. 相似文献
95.
D. Firth C. Payne & J. Payne 《Journal of the Royal Statistical Society. Series A, (Statistics in Society)》1999,162(1):111-120
An evaluation is described of two UK Government programmes for the long-term unemployed in Great Britain, Employment Training and Employment Action, using discrete time hazard modelling of event histories. The study design employed a closely matched comparison group and carefully chosen control variables to minimize the effect of selection bias on conclusions. The effect of unobserved heterogeneity is investigated by using some standard random effect model formulations. 相似文献
96.
Peter Hall & Brett Presnell 《Journal of the Royal Statistical Society. Series B, Statistical methodology》1999,61(3):661-680
Contamination of a sampled distribution, for example by a heavy-tailed distribution, can degrade the performance of a statistical estimator. We suggest a general approach to alleviating this problem, using a version of the weighted bootstrap. The idea is to 'tilt' away from the contaminated distribution by a given (but arbitrary) amount, in a direction that minimizes a measure of the new distribution's dispersion. This theoretical proposal has a simple empirical version, which results in each data value being assigned a weight according to an assessment of its influence on dispersion. Importantly, distance can be measured directly in terms of the likely level of contamination, without reference to an empirical measure of scale. This makes the procedure particularly attractive for use in multivariate problems. It has several forms, depending on the definitions taken for dispersion and for distance between distributions. Examples of dispersion measures include variance and generalizations based on high order moments. Practicable measures of the distance between distributions may be based on power divergence, which includes Hellinger and Kullback–Leibler distances. The resulting location estimator has a smooth, redescending influence curve and appears to avoid computational difficulties that are typically associated with redescending estimators. Its breakdown point can be located at any desired value ε∈ (0, ½) simply by 'trimming' to a known distance (depending only on ε and the choice of distance measure) from the empirical distribution. The estimator has an affine equivariant multivariate form. Further, the general method is applicable to a range of statistical problems, including regression. 相似文献
97.
98.
Zhang Shichang 《电子科技大学学报(社会科学版)》1986,(4)
本文发展了目前回旋管的动力学理论。用动力学方法,描述了回旋潘尼管的不稳定性机理,求解了偶极电流。这样,本文提出的理论,不仅可以更为精确地描写回旋管,而且可以描写新近出现的回旋潘尼管。 相似文献
99.
Fu Chonglun 《电子科技大学学报(社会科学版)》1986,(4)
本文介绍了人机工程学(工效学)这一新兴边缘学科的研究内容、发展及现状,讨论了人-机系统的可靠性并着重讨论了人的操作可靠性,探讨了按人为差错进行可靠性分析与可靠性估计的人为差错和可靠性分析逻辑推演法(HERALD法)及系统能力方法(SC方法)。 本文的结论可供系统管理工作者及设计工作者,特别是可靠性管理及可靠性设计工作者参考。 相似文献
100.
刘锋 《沈阳工业大学学报(社会科学版)》2010,3(4):366-374
企业社会责任等方面存在的问题是造成温州民营企业“民工荒”的重要原因。通过问卷调查,发现员工对企业伦理气候中的法规导向最为认可且看法比较一致,对组织承诺中的情感承诺最为认可且对道德承诺的看法相对一致,对组织公民行为中的组织公益最为认可且看法比较一致。员工对组织承诺、组织公民行为的主张是正向积极的,未发现企业伦理气候、组织承诺对组织公民行为有强烈的正向影响。提出温州民营企业摆脱困境的思路:重视企业伦理气候建设,形成正确的企业文化,增强员工的向心力;强化员工的组织承诺;鼓励员工的组织公民行为。 相似文献