全文获取类型
收费全文 | 7048篇 |
免费 | 166篇 |
国内免费 | 65篇 |
专业分类
管理学 | 297篇 |
民族学 | 28篇 |
人才学 | 4篇 |
人口学 | 63篇 |
丛书文集 | 605篇 |
理论方法论 | 122篇 |
综合类 | 4768篇 |
社会学 | 139篇 |
统计学 | 1253篇 |
出版年
2024年 | 15篇 |
2023年 | 37篇 |
2022年 | 44篇 |
2021年 | 53篇 |
2020年 | 74篇 |
2019年 | 125篇 |
2018年 | 133篇 |
2017年 | 183篇 |
2016年 | 143篇 |
2015年 | 180篇 |
2014年 | 327篇 |
2013年 | 613篇 |
2012年 | 440篇 |
2011年 | 386篇 |
2010年 | 360篇 |
2009年 | 357篇 |
2008年 | 406篇 |
2007年 | 468篇 |
2006年 | 490篇 |
2005年 | 419篇 |
2004年 | 374篇 |
2003年 | 340篇 |
2002年 | 287篇 |
2001年 | 276篇 |
2000年 | 176篇 |
1999年 | 84篇 |
1998年 | 78篇 |
1997年 | 62篇 |
1996年 | 46篇 |
1995年 | 56篇 |
1994年 | 53篇 |
1993年 | 42篇 |
1992年 | 32篇 |
1991年 | 22篇 |
1990年 | 19篇 |
1989年 | 31篇 |
1988年 | 19篇 |
1987年 | 12篇 |
1986年 | 6篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有7279条查询结果,搜索用时 0 毫秒
971.
Remove unwanted variation (RUV) is an estimation and normalization system in which the underlying correlation structure of a multivariate dataset is estimated from negative control measurements, typically gene expression values, which are assumed to stay constant across experimental conditions. In this paper we derive the weight matrix which is estimated and incorporated into the generalized least squares estimates of RUV-inverse, and show that this weight matrix estimates the average covariance matrix across negative control measurements. RUV-inverse can thus be viewed as an estimation method adjusting for an unknown experimental design. We show that for a balanced incomplete block design (BIBD), RUV-inverse recovers intra- and interblock estimates of the relevant parameters and combines them as a weighted sum just like the best linear unbiased estimator (BLUE), except that the weights are globally estimated from the negative control measurements instead of being individually optimized to each measurement as in the classical, single measurement BIBD BLUE. 相似文献
972.
Gaohong Dong David C. Hoaglin Bo Huang Ying Cui Duolao Wang Yu Cheng Margaret Gamalo-Siebers 《Pharmaceutical statistics》2023,22(4):748-756
The win odds and the net benefit are related directly to each other and indirectly, through ties, to the win ratio. These three win statistics test the same null hypothesis of equal win probabilities between two groups. They provide similar p-values and powers, because the Z-values of their statistical tests are approximately equal. Thus, they can complement one another to show the strength of a treatment effect. In this article, we show that the estimated variances of the win statistics are also directly related regardless of ties or indirectly related through ties. Since its introduction in 2018, the stratified win ratio has been applied in designs and analyses of clinical trials, including Phase III and Phase IV studies. This article generalizes the stratified method to the win odds and the net benefit. As a result, the relations of the three win statistics and the approximate equivalence of their statistical tests also hold for the stratified win statistics. 相似文献
973.
On the probability distribution of economic growth 总被引:1,自引:0,他引:1
Three important and significantly heteroscedastic gross domestic product series are studied. Omnipresent heteroscedasticity is removed and the distributions of the series are then compared to normal, normal mixture and normal–asymmetric Laplace (NAL) distributions. NAL represents a skewed and leptokurtic distribution, which is in line with the Aghion and Howitt [1] model for economic growth, based on Schumpeter's idea of creative destruction. Statistical properties of the NAL distributions are provided and it is shown that NAL fits the data better than the alternatives. 相似文献
974.
Statistical agencies have conflicting obligations to protect confidential information provided by respondents to surveys or censuses and to make data available for research and planning activities. When the microdata themselves are to be released, in order to achieve these conflicting objectives, statistical agencies apply statistical disclosure limitation (SDL) methods to the data, such as noise addition, swapping or microaggregation. Some of these methods do not preserve important structure and constraints in the data, such as positivity of some attributes or inequality constraints between attributes. Failure to preserve constraints is not only problematic in terms of data utility, but also may increase disclosure risk.In this paper, we describe a method for SDL that preserves both positivity of attributes and the mean vector and covariance matrix of the original data. The basis of the method is to apply multiplicative noise with the proper, data-dependent covariance structure. 相似文献
975.
Panel data with covariate measurement error appear frequently in various studies. Due to the sampling design and/or missing data, panel data are often unbalanced in the sense that panels have different sizes. For balanced panel data (i.e., panels having the same size), there exists a generalized method of moments (GMM) approach for adjusting covariate measurement error, which does not require additional validation data. This paper extends the GMM approach of adjusting covariate measurement error to unbalanced panel data. Two health related longitudinal surveys are used to illustrate the implementation of the proposed method. 相似文献
976.
Yong Zhou Alan T.K. Wan Yuan Yuan 《Journal of statistical planning and inference》2011,141(12):3814-3828
Least-squares and quantile regressions are method of moments techniques that are typically used in isolation. A leading example where efficiency may be gained by combining least-squares and quantile regressions is one where some information on the error quantiles is available but the error distribution cannot be fully specified. This estimation problem may be cast in terms of solving an over-determined estimating equation (EE) system for which the generalized method of moments (GMM) and empirical likelihood (EL) are approaches of recognized importance. The major difficulty with implementing these techniques here is that the EEs associated with the quantiles are non-differentiable. In this paper, we develop a kernel-based smoothing technique for non-smooth EEs, and derive the asymptotic properties of the GMM and maximum smoothed EL (MSEL) estimators based on the smoothed EEs. Via a simulation study, we investigate the finite sample properties of the GMM and MSEL estimators that combine least-squares and quantile moment relationships. Applications to real datasets are also considered. 相似文献
977.
基于MC模拟方法研究了格兰杰伪因果关系的小样本性质,结果表明伪因果关系的发生概率会随着数据过程持久性的增强而增大,但会随着样本容量的增加而减少,且由于检验式的设定使得经Newey-West修正的检验方法并没有明显优势。通过解释变量和被解释变量的持久性对伪因果关系的影响以及与OLS估计的伪回归比较分析,表明随机干扰项的自相关或异方差是产生伪因果关系的主要原因,这为解决伪回归和伪因果关系问题提供了统一研究框架。 相似文献
978.
线性回归模型Bootstrap LM-Lag检验有效性研究 总被引:2,自引:0,他引:2
基于OLS估计残差,将Bootstrap方法用于空间滞后相关LM-Lag检验。在不同的误差结构和空间权重矩阵条件下,比较Bootstrap LM-Lag检验和渐近检验的水平扭曲和功效。通过Monte Carlo实验表明,当误差项不服从经典正态分布假设时,LM-Lag渐近检验存在严重的水平扭曲,Bootstrap检验能够有效地校正水平扭曲,并且Bootstrap LM-Lag检验的功效与渐近检验近似;无论误差项是否服从正态分布,从水平扭曲和功效角度看,线性回归模型Bootstrap LM-Lag检验有效。 相似文献
979.
Adrian Baddeley 《Australian & New Zealand Journal of Statistics》2011,53(3):365-387
In survey sampling and in stereology, it is often desirable to estimate the ratio of means θ= E(Y)/E(X) from bivariate count data (X, Y) with unknown joint distribution. We review methods that are available for this problem, with particular reference to stereological applications. We also develop new methods based on explicit statistical models for the data, and associated model diagnostics. The methods are tested on a stereological dataset. For point‐count data, binomial regression and bivariate binomial models are generally adequate. Intercept‐count data are often overdispersed relative to Poisson regression models, but adequately fitted by negative binomial regression. 相似文献
980.
We present a new method for decomposing a social network into an optimal number of hierarchical subgroups. With a perfect hierarchical subgroup defined as one in which every member is automorphically equivalent to each other, the method uses the REGGE algorithm to measure the similarities among nodes and applies the k-means method to group the nodes that have congruent profiles of dissimilarities with other nodes into various numbers of hierarchical subgroups. The best number of subgroups is determined by minimizing the intra-cluster variance of dissimilarity subject to the constraint that the improvement in going to more subgroups is better than a network whose n nodes are maximally dispersed in the n-dimensional space would achieve. We also describe a decomposability metric that assesses the deviation of a real network from the ideal one that contains only perfect hierarchical subgroups. Four well known network data sets are used to demonstrate the method and metric. These demonstrations indicate the utility of our approach and suggest how it can be used in a complementary way to Generalized Blockmodeling for hierarchical decomposition. 相似文献