全文获取类型
收费全文 | 15747篇 |
免费 | 423篇 |
专业分类
管理学 | 2207篇 |
民族学 | 73篇 |
人才学 | 1篇 |
人口学 | 1640篇 |
丛书文集 | 77篇 |
教育普及 | 2篇 |
理论方法论 | 1396篇 |
现状及发展 | 1篇 |
综合类 | 189篇 |
社会学 | 7440篇 |
统计学 | 3144篇 |
出版年
2023年 | 105篇 |
2021年 | 99篇 |
2020年 | 242篇 |
2019年 | 325篇 |
2018年 | 381篇 |
2017年 | 526篇 |
2016年 | 409篇 |
2015年 | 255篇 |
2014年 | 356篇 |
2013年 | 2646篇 |
2012年 | 512篇 |
2011年 | 439篇 |
2010年 | 364篇 |
2009年 | 341篇 |
2008年 | 395篇 |
2007年 | 386篇 |
2006年 | 380篇 |
2005年 | 364篇 |
2004年 | 342篇 |
2003年 | 284篇 |
2002年 | 333篇 |
2001年 | 391篇 |
2000年 | 392篇 |
1999年 | 386篇 |
1998年 | 271篇 |
1997年 | 248篇 |
1996年 | 246篇 |
1995年 | 224篇 |
1994年 | 187篇 |
1993年 | 228篇 |
1992年 | 250篇 |
1991年 | 233篇 |
1990年 | 230篇 |
1989年 | 251篇 |
1988年 | 208篇 |
1987年 | 195篇 |
1986年 | 207篇 |
1985年 | 233篇 |
1984年 | 227篇 |
1983年 | 221篇 |
1982年 | 160篇 |
1981年 | 142篇 |
1980年 | 135篇 |
1979年 | 182篇 |
1978年 | 123篇 |
1977年 | 118篇 |
1976年 | 117篇 |
1975年 | 111篇 |
1974年 | 117篇 |
1973年 | 98篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
James P. McDermott G. Jogesh Babu John C. Liechty Dennis K. J. Lin 《Statistics and Computing》2007,17(4):311-321
We consider the problem of density estimation when the data is in the form of a continuous stream with no fixed length. In
this setting, implementations of the usual methods of density estimation such as kernel density estimation are problematic.
We propose a method of density estimation for massive datasets that is based upon taking the derivative of a smooth curve
that has been fit through a set of quantile estimates. To achieve this, a low-storage, single-pass, sequential method is proposed
for simultaneous estimation of multiple quantiles for massive datasets that form the basis of this method of density estimation.
For comparison, we also consider a sequential kernel density estimator. The proposed methods are shown through simulation
study to perform well and to have several distinct advantages over existing methods. 相似文献
102.
103.
Nicholas T. Longford 《Statistics and Computing》2003,13(1):67-80
The weaknesses of established model selection procedures based on hypothesis testing and similar criteria are discussed and an alternative based on synthetic (composite) estimation is proposed. It is developed for the problem of prediction in ordinary regression and its properties are explored by simulations for the simple regression. Extensions to a general setting are described and an example with multiple regression is analysed. Arguments are presented against using a selected model for any inferences. 相似文献
104.
105.
It is well known that the unimodal maximum likelihood estimator of a density is consistent everywhere but at the mode. The authors review various ways to solve this problem and propose a new estimator that is concave over an interval containing the mode; this interval may be chosen by the user or through an algorithm. The authors show how to implement their solution and compare it to other approaches through simulations. They show that the new estimator is consistent everywhere and determine its rate of convergence in the Hellinger metric. 相似文献
106.
C. A. Glasbey D. J. Allcroft 《Journal of the Royal Statistical Society. Series C, Applied statistics》2008,57(3):343-355
Summary. To investigate the variability in energy output from a network of photovoltaic cells, solar radiation was recorded at 10 sites every 10 min in the Pentland Hills to the south of Edinburgh. We identify spatiotemporal auto-regressive moving average models as the most appropriate to address this problem. Although previously considered computationally prohibitive to work with, we show that by approximating using toroidal space and fitting by matching auto-correlations, calculations can be substantially reduced. We find that a first-order spatiotemporal auto-regressive (STAR(1)) process with a first-order neighbourhood structure and a Matern noise process provide an adequate fit to the data, and we demonstrate its use in simulating realizations of energy output. 相似文献
107.
108.
The ability to infer parameters of gene regulatory networks is emerging as a key problem in systems biology. The biochemical
data are intrinsically stochastic and tend to be observed by means of discrete-time sampling systems, which are often limited
in their completeness. In this paper we explore how to make Bayesian inference for the kinetic rate constants of regulatory
networks, using the stochastic kinetic Lotka-Volterra system as a model. This simple model describes behaviour typical of
many biochemical networks which exhibit auto-regulatory behaviour. Various MCMC algorithms are described and their performance
evaluated in several data-poor scenarios. An algorithm based on an approximating process is shown to be particularly efficient. 相似文献
109.
Yen Steven T. Douglass Shaw W. Eiswerth Mark E. 《Review of Economics of the Household》2004,2(1):73-88
Asthma patients' health status may be especially sensitive to some types of air pollution, but the evidence on this is mixed. We explore the effects of ground-level ozone on asthma patient's activities, breaking apart the usual aggregated category of leisure into indoor and outdoor activities, and differentiating those by whether the activities were active or inactive. Applying the semiparametric censored estimation method we demonstrate that even though the period over which activities were observed was relatively low in ozone levels, there is a significant impact of ozone on a few activities. The (non-ozone) economic and demographic variables in the model play significant roles in explaining the allocation of time among seven activities, suggesting the suitability of the approach for other household decision-making contexts. 相似文献
110.
Terence C. Mills 《Journal of applied statistics》2008,35(10):1131-1138
While body fat is the most accurate measure of obesity, its measurement requires special equipment that can be costly and time consuming to operate. Attention has thus typically focused on the easier to calculate body mass index (BMI). However, the ability of BMI to accurately identify obesity has been increasingly questioned. This paper focuses attention on whether more general body mass indices are appropriate measures of body fat. Using a data set of body fat, height, and weight measurements, general models are estimated which nest a wide variety of weight–height indices as special cases. In the absence of a race and gender categorisation, the conventional BMI was found to be the appropriate index with which to predict body fat. When such a categorisation was made, however, the BMI was never selected as the appropriate index. In general, predicted female body fat was some 10 kg higher than that of a male of identical build and predicted % body fat was over 11 percentage points higher, but age effects were smaller for females. Considerable racial differences in predicted body fat were found for males, but such differences were less marked for females. The implications of this finding for interpreting recent research on the effect of obesity on health, society, and economic factors are considered. 相似文献