全文获取类型
收费全文 | 3356篇 |
免费 | 81篇 |
国内免费 | 10篇 |
专业分类
管理学 | 173篇 |
民族学 | 5篇 |
人才学 | 1篇 |
人口学 | 39篇 |
丛书文集 | 88篇 |
理论方法论 | 30篇 |
综合类 | 944篇 |
社会学 | 42篇 |
统计学 | 2125篇 |
出版年
2024年 | 3篇 |
2023年 | 9篇 |
2022年 | 28篇 |
2021年 | 19篇 |
2020年 | 54篇 |
2019年 | 80篇 |
2018年 | 104篇 |
2017年 | 163篇 |
2016年 | 78篇 |
2015年 | 85篇 |
2014年 | 121篇 |
2013年 | 862篇 |
2012年 | 258篇 |
2011年 | 125篇 |
2010年 | 157篇 |
2009年 | 121篇 |
2008年 | 134篇 |
2007年 | 119篇 |
2006年 | 136篇 |
2005年 | 111篇 |
2004年 | 91篇 |
2003年 | 92篇 |
2002年 | 66篇 |
2001年 | 75篇 |
2000年 | 68篇 |
1999年 | 52篇 |
1998年 | 37篇 |
1997年 | 35篇 |
1996年 | 31篇 |
1995年 | 25篇 |
1994年 | 12篇 |
1993年 | 15篇 |
1992年 | 17篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 1篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 3篇 |
排序方式: 共有3447条查询结果,搜索用时 0 毫秒
201.
This article considers the notion of the non-diagonal-type estimator (NDTE) under the prediction error sum of squares (PRESS) criterion. First, the optimal NDTE in the PRESS sense is derived theoretically and applied to the cosmetics sales data. Second, we make a further study to extend the NDTE to the general case of the covariance matrix of the model and then give a Bayesian explanation for this extension. Third, two remarks concerned with some potential shortcomings of the NDTE are presented and an alternative solution is provided and illustrated by means of simulations. 相似文献
202.
Feng-Shou Ko 《统计学通讯:理论与方法》2014,43(1):72-89
In this article, we discuss how to identify longitudinal biomarkers in survival analysis under the accelerated failure time model and also discuss the effectiveness of biomarkers under the accelerated failure time model. Two methods proposed by Shcemper et al. are deployed to measure the efficacy of biomarkers. We use simulations to explore how the factors can influence the power of a score test to detect the association of a longitudinal biomarker and the survival time. These factors include the functional form of the random effects from the longitudinal biomarkers, in the different number of individuals, and time points per individual. The simulations are used to explore how the number of individuals, the number of time points per individual influence the effectiveness of the biomarker to predict survival at the given endpoint under the accelerated failure time model. We illustrate our methods using a prothrombin index as a predictor of survival in liver cirrhosis patients. 相似文献
203.
《统计学通讯:理论与方法》2013,42(6):943-960
ABSTRACT We study the estimation of a hazard rate function based on censored data by non-linear wavelet method. We provide an asymptotic formula for the mean integrated squared error (MISE) of nonlinear wavelet-based hazard rate estimators under randomly censored data. We show this MISE formula, when the underlying hazard rate function and censoring distribution function are only piecewise smooth, has the same expansion as analogous kernel estimators, a feature not available for the kernel estimators. In addition, we establish an asymptotic normality of the nonlinear wavelet estimator. 相似文献
204.
Burkhard O. Rauhut 《统计学通讯:理论与方法》2013,42(13):1439-1452
Given a life testing experiment consisting of n items, n-1 of which have the expected life λ while one could have an expected life λ/α with 0 < α < 1 the problem is. to find a mean square error (MSE) minimizing estimation function. The standard estimators for the homogeneous case (α = 1) overestimate the expected life and their MSE tend to infinity when a tends to 0. Looking at the estimation problem as an insurance (see Anscombe (1960)) two different “testimators” are compared with respect to their MSE, Numerical results show that an estimation function based on the “Epstein-statistic” x(n)/[xbar] is the best one. 相似文献
205.
206.
《商业与经济统计学杂志》2013,31(3):380-382
In a recent article by Qi, neural networks trained by Bayesian regularization were used to predict excess returns on the S&P 500. The article concluded that the switching portfolio based on the recursive neural-network forecasts generates higher accumulated wealth with lower risks than that based on linear regression. Unfortunately, attempts to replicate the results were unsuccessful. Replicated results using the same software, approach and data detailed by Qi indicate that, in fact, the switching portfolio based on the recursive neural-network forecasts generates lower accumulated wealth with higher risks than that based on linear regression. 相似文献
207.
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
208.
介绍了溶液中弱电解质平衡体系的pH计算是《无机化学》课程中的重要基础理论知识。为简化计算经常需要引入近似条件,这样必然造成误差。通过理论计算解释了不同c/ka^o值与解离度误差的关系和不同解离度误差对应的c/ka^o值,对学生正确理解相关内容大有助益,是教材内容的必要补充。 相似文献
209.
Ravindra Khattree 《统计学通讯:理论与方法》2013,42(1):263-274
In this paper, estimates QP dispersion matrix and its functions are compared based on generalized Pitman nearness criterion, Various Iosa functions are considered for the purpose. Locally superior estimates are defined and obtained. Comparison of these estimates are made with other standard ones. It is snown that within certain classes, defined in the paper, these are the best estimatcrs ia the generalized Fitman nearness sense 相似文献
210.
Some degree of error is inevitable in multi‐agent bioassays regardless of design or measurement technology. Estimation error can be reduced post facto by exploiting the matrix partial ordering of the bioassay survival estimates. The standard method for this is order‐restricted regression (ORR). If the joint action of the bioassay agents admits a tolerance‐based interpretation, additional structure beyond matrix partial ordering is available, leading to a new method of error reduction. This tolerance‐based error reduction (TBER) procedure almost always outperforms ORR. Like ORR, TBER applies to complete factorial bioassay designs and, using weighting, to incomplete designs. 相似文献