全文获取类型
收费全文 | 957篇 |
免费 | 20篇 |
国内免费 | 9篇 |
专业分类
管理学 | 66篇 |
民族学 | 1篇 |
人口学 | 4篇 |
丛书文集 | 9篇 |
理论方法论 | 7篇 |
综合类 | 280篇 |
社会学 | 2篇 |
统计学 | 617篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 4篇 |
2020年 | 19篇 |
2019年 | 25篇 |
2018年 | 33篇 |
2017年 | 42篇 |
2016年 | 33篇 |
2015年 | 31篇 |
2014年 | 28篇 |
2013年 | 243篇 |
2012年 | 65篇 |
2011年 | 34篇 |
2010年 | 25篇 |
2009年 | 33篇 |
2008年 | 32篇 |
2007年 | 25篇 |
2006年 | 27篇 |
2005年 | 32篇 |
2004年 | 25篇 |
2003年 | 24篇 |
2002年 | 24篇 |
2001年 | 16篇 |
2000年 | 14篇 |
1999年 | 13篇 |
1998年 | 13篇 |
1997年 | 26篇 |
1996年 | 9篇 |
1995年 | 13篇 |
1994年 | 11篇 |
1993年 | 7篇 |
1992年 | 6篇 |
1991年 | 11篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 8篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1978年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有986条查询结果,搜索用时 109 毫秒
91.
信息图像化是一个受到广泛重视的研究课题,而图像的定量分析关系到图像中所包含的信息能否被很好的提取和利用.本文介绍了图像分析技术的原理及过程,着重介绍了自行研制的图像分析仪的应用实例. 相似文献
92.
中国陆相地层岩性成分较为复杂,岩性波阻抗值常呈多极分布。水动能强度的急剧变化、高频率的水进水退等沉积背景造成了薄互层广泛发育的特点。储层间干涉现象普遍存在,直接影响到地震岩性解释的精度。针对复杂岩性地区岩性–波阻抗关系复杂的特点,系统分析了造成传统地震储层预测方法解释误差的原因。根据复杂岩性的地球物理响应特点,选取对区分复杂岩性敏感的测井参数。同时,将90° 相位化地震数据作为测井参数反演的相对波阻抗约束数据体。研究结果表明,该方法对复杂岩性进行了有效的区分,达到了精细描述复杂岩性地区储层空间发育及平面展布特点的目的。 相似文献
93.
对影响水平井水平段延伸能力的因素进行了分析,然后根据钻井液流体力学理论,建立了水平井循环压耗计算模型,分别对水平井总循环压耗和水平段环空压耗进行计算,进而求出了水平井水平段极限延伸长度值;对钻井液密度、钻井泵额定压力、岩屑床高度和钻井液排量对水平段水力延伸能力的影响进行了分析。研究表明,水平段水力延伸能力受钻井液密度、钻井泵额定压力、岩屑床高度和钻井液排量等多个因素共同影响。为了提高深井水平井的延伸能力,应使用较低密度的钻井液;尽量保持较低的岩屑床高度;钻井液排量应尽量小。同时还认识到,深井水平井水力延伸能力主要受到钻井泵额定压力的制约。研发高额定压力的钻井泵,是提高深井水平井水力延伸能力的主要措施。 相似文献
94.
We consider a stochastic differential equation involving standard and fractional Brownian motion with unknown drift parameter to be estimated. We investigate the standard maximum likelihood estimate of the drift parameter, two non-standard estimates and three estimates for the sequential estimation. Model strong consistency and some other properties are proved. The linear model and Ornstein–Uhlenbeck model are studied in detail. As an auxiliary result, an asymptotic behaviour of the fractional derivative of the fractional Brownian motion is established. 相似文献
95.
Threshold‐free estimation of functional antibody titers of a group B streptococcus opsonophagocytic killing assay
下载免费PDF全文
![点击此处可从《Pharmaceutical statistics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Luca Moraschini Irene Passalacqua Monica Fabbrini Immaculada Margarit Y Ros Fabio Rigat 《Pharmaceutical statistics》2015,14(3):189-197
Opsonophagocytic killing assays (OPKA) are routinely used for the quantification of bactericidal antibodies in blood serum samples. Quantification of the OPKA readout, the titer, provides the basis for the statistical analysis of vaccine clinical trials having functional immune response endpoints. Traditional OPKA titers are defined as the maximum serum dilution yielding a predefined bacterial killing threshold value, and they are estimated by fitting a dose‐response model to the dilution‐killing curve. This paper illustrates a novel definition of titer, the threshold‐free titer, which preserves biological interpretability while not depending on any killing threshold or on a postulated shape of the dose‐response curve. These titers are shown to be more precise than the traditional threshold‐based titers when using simulated and experimental group B streptococcus OPKA experimental data. Also, titer linearity is shown to be not measurable when using threshold‐based titers, whereas it becomes measurable using threshold‐free titers. The biological interpretability and operational characteristics demonstrated here indicate that threshold‐free titers are an appropriate tool for the routine analysis of OPKA data. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
96.
In this paper, we are interested in the weighted distributions of a bivariate three parameter logarithmic series distribution studied by Kocherlakota and Kocherlakota (1990). The weighted versions of the model are derived with weight W(x,y) = x[r] y[s]. Explicit expressions for the probability mass function and probability generating functions are derived in the case r = s = l. The marginal and conditional distributions are derived in the general case. The maximum likelihood estimation of the parameters, in both two parameter and three parameter cases, is studied. A procedure for computer generation of bivariate data from a discrete distribution is described. This enables us to present two examples, in order to illustrate the methods developed, for finding the maximum likelihood estimates. 相似文献
97.
仿人智能控制器(HSIC)是一类实时鲁棒的智能控制器,被成功用于不少工业过程,但在实际应用中,控制器参数的整定仍然依靠专家来进行,考虑到HSIC控制器参数与系统闭环响应过程特征参数之间的模糊关系,本文提出了一类基于模糊推理的参数自整定方法并用于温度对象的控制中,表明该方法是有效的。 相似文献
98.
Victor M. Guerrero 《统计学通讯:理论与方法》2013,42(21):4568-4585
We consider the problem of estimating a trend with different amounts of smoothness for segments of a time series subjected to different variability regimes. We propose using an unobserved components model to consider the existence of at least two data segments. We first fix some desired percentages of smoothness for the trend segments and deduce the corresponding smoothing parameters involved. Once the size of each segment is chosen, the smoothing formulas here derived produce trend estimates for all segments with the desired smoothness as well as their corresponding estimated variances. Empirical examples from demography and economics illustrate our proposal. 相似文献
99.
Birgitta Törnkvist 《统计学通讯:模拟与计算》2013,42(4):1247-1264
In modelling a system structure it is often important to test the constancy of the structural parameters. If the hypothesis of constant parameters is rejected we wish to characterize the parameter variation. In this paper we examine the usefulness of the MOSUMSQ test statistics for locating and characterizing the parameter variation in linear regression models. The means and the variances of the test statistics are given for non-random parameter variation. The observed path of the MOSUMSQ test statistics provides valuable knowledge about the time of the onset of the parameter change and whether it is instantaneous or gradual. 相似文献
100.
Beiyao Zheng 《统计学通讯:理论与方法》2013,42(5-6):1405-1417
We propose Bayesian parameter estimation in a multidimensional item response theory model using the Gibbs sampling algorithm. We apply this approach to dichotomous responses to a questionnaire on sleep quality. The analysis helps determine the underlying dimensions. 相似文献