全文获取类型
收费全文 | 1300篇 |
免费 | 42篇 |
国内免费 | 20篇 |
专业分类
管理学 | 90篇 |
民族学 | 6篇 |
人口学 | 19篇 |
丛书文集 | 67篇 |
理论方法论 | 33篇 |
综合类 | 444篇 |
社会学 | 76篇 |
统计学 | 627篇 |
出版年
2024年 | 1篇 |
2023年 | 13篇 |
2022年 | 10篇 |
2021年 | 14篇 |
2020年 | 28篇 |
2019年 | 38篇 |
2018年 | 52篇 |
2017年 | 91篇 |
2016年 | 23篇 |
2015年 | 37篇 |
2014年 | 54篇 |
2013年 | 198篇 |
2012年 | 101篇 |
2011年 | 62篇 |
2010年 | 62篇 |
2009年 | 62篇 |
2008年 | 59篇 |
2007年 | 53篇 |
2006年 | 52篇 |
2005年 | 64篇 |
2004年 | 45篇 |
2003年 | 32篇 |
2002年 | 36篇 |
2001年 | 41篇 |
2000年 | 16篇 |
1999年 | 24篇 |
1998年 | 12篇 |
1997年 | 19篇 |
1996年 | 11篇 |
1995年 | 13篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
排序方式: 共有1362条查询结果,搜索用时 156 毫秒
1.
2.
Proportional hazards are a common assumption when designing confirmatory clinical trials in oncology. This assumption not only affects the analysis part but also the sample size calculation. The presence of delayed effects causes a change in the hazard ratio while the trial is ongoing since at the beginning we do not observe any difference between treatment arms, and after some unknown time point, the differences between treatment arms will start to appear. Hence, the proportional hazards assumption no longer holds, and both sample size calculation and analysis methods to be used should be reconsidered. The weighted log‐rank test allows a weighting for early, middle, and late differences through the Fleming and Harrington class of weights and is proven to be more efficient when the proportional hazards assumption does not hold. The Fleming and Harrington class of weights, along with the estimated delay, can be incorporated into the sample size calculation in order to maintain the desired power once the treatment arm differences start to appear. In this article, we explore the impact of delayed effects in group sequential and adaptive group sequential designs and make an empirical evaluation in terms of power and type‐I error rate of the of the weighted log‐rank test in a simulated scenario with fixed values of the Fleming and Harrington class of weights. We also give some practical recommendations regarding which methodology should be used in the presence of delayed effects depending on certain characteristics of the trial. 相似文献
3.
4.
熊欣 《齐齐哈尔大学学报(哲学社会科学版)》2003,(4):115-117
正确把握语调变体是言语交际成败的关键;口语中不同语调的使用表述了说话人不同的思想感情和态度.也正是这种语用语调的变异导致了语义理解和思想表达的细微差别,差之毫厘,谬以千里.本文从语调功能,常规语调运用及语调变体三个角度,以翔实的例句分析,对英语语调变体进行解构. 相似文献
5.
Diagnostics for dependence within time series extremes 总被引:1,自引:0,他引:1
Anthony W. Ledford Jonathan A. Tawn 《Journal of the Royal Statistical Society. Series B, Statistical methodology》2003,65(2):521-543
Summary. The analysis of extreme values within a stationary time series entails various assumptions concerning its long- and short-range dependence. We present a range of new diagnostic tools for assessing whether these assumptions are appropriate and for identifying structure within extreme events. These tools are based on tail characteristics of joint survivor functions but can be implemented by using existing estimation methods for extremes of univariate independent and identically distributed variables. Our diagnostic aids are illustrated through theoretical examples, simulation studies and by application to rainfall and exchange rate data. On the basis of these diagnostics we can explain characteristics that are found in the observed extreme events of these series and also gain insight into the properties of events that are more extreme than those observed. 相似文献
6.
首先分析了对数最小二乘排序法的特点,说明它是一种值得重视的好方法;并进一步阐述了这一方法的基本原理,着重地对群体判断下求加权的综合排序向量的方法进行了严密的数学推导;提出了在加权的综合排序中权重系数确定的新見解,并举例子以解释。 相似文献
7.
CUI Jin-lan 《中央民族大学学报(哲学社会科学版)》2006,(4)
从音乐形态、表现手法等方面具体分析《变奏曲》这部钢琴作品,探究其中对中国传统戏曲效果的模拟,以及作者如何巧妙地借鉴皮黄丰富的音响和表现力并运用到钢琴音乐中。中西的结合,古今的碰撞、鲜明的色彩个性,这些特点使得这部作品成为探索中国钢琴音乐民族化道路上的闪光点。 相似文献
8.
论速度变化对标枪成绩的影响 总被引:1,自引:0,他引:1
周二三 《广州大学学报(社会科学版)》2002,1(6):94-96
本文就网络英语教学目前存在的认识上的误区、大学英语网络教学目前可采用的基本模式以及大学英语网络教学的优越性和目前存在的问题进行探讨 相似文献
9.
Chris J. Lloyd 《Australian & New Zealand Journal of Statistics》2002,44(1):75-86
This paper presents a method of estimating a receiver operating characteristic (ROC) curve when the underlying diagnostic variable X is continuous and fully observed. The new method is based on modelling the probability of response given X , rather than the distribution of X given response. The method offers advantages in modelling flexibility and computational simplicity. The resulting ROC curve estimates are semi-parametric and can, in principle, take an infinite variety of shapes. Moreover, model selection can be based on standard methods within the binomial regression framework. Statistical accuracy of the curve estimate is provided by a simply implemented bootstrap approach. 相似文献
10.
WEIGHTED SUMS OF NEGATIVELY ASSOCIATED RANDOM VARIABLES 总被引:2,自引:0,他引:2
In this paper, we establish strong laws for weighted sums of negatively associated (NA) random variables which have a higher‐order moment condition. Some results of Bai Z.D. & Cheng P.E. (2000) [Marcinkiewicz strong laws for linear statistics. Statist. and Probab. Lett. 43, 105–112,] and Sung S.K. (2001) [Strong laws for weighted sums of i.i.d. random variables, Statist. and Probab. Lett. 52, 413–419] are sharpened and extended from the independent identically distributed case to the NA setting. Also, one of the results of Li D.L. et al. (1995) [Complete convergence and almost sure convergence of weighted sums of random variables. J. Theoret. Probab. 8, 49–76,] is complemented and extended. 相似文献