首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   14098篇
  免费   339篇
  国内免费   146篇
管理学   428篇
劳动科学   2篇
民族学   72篇
人才学   5篇
人口学   247篇
丛书文集   1296篇
理论方法论   578篇
综合类   8520篇
社会学   1022篇
统计学   2413篇
  2024年   28篇
  2023年   101篇
  2022年   111篇
  2021年   154篇
  2020年   223篇
  2019年   307篇
  2018年   306篇
  2017年   404篇
  2016年   315篇
  2015年   426篇
  2014年   1140篇
  2013年   1899篇
  2012年   1340篇
  2011年   987篇
  2010年   960篇
  2009年   826篇
  2008年   807篇
  2007年   587篇
  2006年   573篇
  2005年   517篇
  2004年   473篇
  2003年   465篇
  2002年   394篇
  2001年   331篇
  2000年   214篇
  1999年   97篇
  1998年   90篇
  1997年   70篇
  1996年   51篇
  1995年   66篇
  1994年   59篇
  1993年   48篇
  1992年   34篇
  1991年   24篇
  1990年   23篇
  1989年   36篇
  1988年   24篇
  1987年   12篇
  1986年   10篇
  1985年   6篇
  1984年   9篇
  1983年   6篇
  1982年   4篇
  1981年   11篇
  1980年   5篇
  1979年   5篇
  1978年   3篇
  1977年   1篇
  1976年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
彭道宾 《统计研究》2011,28(1):106-112
 中央苏区制发了众多的统计报表全面反映战争和建设情况,采取多种调查统计方法确保数据真实可靠,并利用丰富的调查统计资料积极开展统计分析,及时发布统计资料,为革命战争和苏区经济建设服务。  相似文献   
992.
The Gibbs sampler has been proposed as a general method for Bayesian calculation in Gelfand and Smith (1990). However, the predominance of experience to date resides in applications assuming conjugacy where implementation is reasonably straightforward. This paper describes a tailored approximate rejection method approach for implementation of the Gibbs sampler when nonconjugate structure is present. Several challenging applications are presented for illustration.  相似文献   
993.
示波极谱滴定——NaNO_2法具有快速准确的特点。本文报道了在40mL 6mol/L HCI—1.5g KBr的溶液中,以微铂电极为指示电极,以铂片电极作为参比电极,采用示波极谱滴定——NaNO_2法测定了非那西丁。通过ι检验,该法与药典法所测结果无显著性差异,表明该法可靠。  相似文献   
994.
用于电磁逆散射问题中关于未知介质分布的非线性积分方程经离散化后,其相应的矩阵方程通常是病态方程。对于病态的矩阵方程,其解或是不存在或是不唯一。这取决于该矩阵方程是超定的还是欠定的。对于这样的不适定问题,可用一些泛函方法使其转化为适定问题。文中介绍了用于电磁逆散射问题中的最小二乘方法、奇异值分解方法、正则化方法和最大熵方法,并对各种方法的优缺点给出评价。  相似文献   
995.
A central part of probabilistic public health risk assessment is the selection of probability distributions for the uncertain input variables. In this paper, we apply the first-order reliability method (FORM)(1–3) as a probabilistic tool to assess the effect of probability distributions of the input random variables on the probability that risk exceeds a threshold level (termed the probability of failure) and on the relevant probabilistic sensitivities. The analysis was applied to a case study given by Thompson et al. (4) on cancer risk caused by the ingestion of benzene contaminated soil. Normal, lognormal, and uniform distributions were used in the analysis. The results show that the selection of a probability distribution function for the uncertain variables in this case study had a moderate impact on the probability that values would fall above a given threshold risk when the threshold risk is at the 50th percentile of the original distribution given by Thompson et al. (4) The impact was much greater when the threshold risk level was at the 95th percentile. The impact on uncertainty sensitivity, however, showed a reversed trend, where the impact was more appreciable for the 50th percentile of the original distribution of risk given by Thompson et al. 4 than for the 95th percentile. Nevertheless, the choice of distribution shape did not alter the order of probabilistic sensitivity of the basic uncertain variables.  相似文献   
996.
Adaptive allocations in stratified sampling design are suitable for studying Biological and Environmental populations. Biologists tend to use the conventional stratified estimator for an adaptive allocation sampling design in spite of its adaptive nature. In this paper, we have introduced an adaptive allocation sampling design for which the conventional stratified estimator has some desired statistical properties. We conduct a simulation study on a real population. The results show that the conventional stratified estimator for the introduced adaptive allocation sampling design is more efficient than other available estimators.  相似文献   
997.
In this note, we focus on estimating the false discovery rate (FDR) of a multiple testing method with a common, non-random rejection threshold under a mixture model. We develop a new class of estimates of the FDR and prove that it is less conservatively biased than what is traditionally used. Numerical evidence is presented to show that the mean squared error (MSE) is also often smaller for the present class of estimates, especially in small-scale multiple testings. A similar class of estimates of the positive false discovery rate (pFDR) less conservatively biased than what is usually used is then proposed. When modified using our estimate of the pFDR and applied to a gene-expression data, Storey's q-value method identifies a few more significant genes than his original q-value method at certain thresholds. The BH like method developed by thresholding our estimate of the FDR is shown to control the FDR in situations where the p  -values have the same dependence structure as required by the BH method and, for lack of information about the proportion π0π0 of true null hypotheses, it is reasonable to assume that π0π0 is uniformly distributed over (0,1).  相似文献   
998.
It is shown in this paper that the parameters of a multinomial distribution may be re-parameterized as a set of generalized Simpson's diversity indices. There are two important elements in the generalization: (1) Simpson's diversity index is extended to populations with infinite species; (2) weighting schemes are incorporated. A class of unbiased estimators for the generalized Simpson's biodiversity indices is proposed. Asymptotic normality is established for the estimators. Both the unbiasedness and the asymptotic normality of the estimators hold for all three cases of the number of species in the population: infinite, finite and known, and finite but unknown. In the case of a population with a finite number of species, known or unknown, it is also established that the proposed estimators are uniformly minimum variance unbiased and are asymptotically efficient.  相似文献   
999.
This paper provides tables for the construction and selection of tightened–normal–tightened variables sampling scheme of type TNTVSS (n 1, n 2; k). The method of designing the scheme indexed by (AQL, α) and (LQL, β) is indicated. The TNTVSS (n T , n N; k) is compared with conventional single sampling plans for variables and with TNT (n 1, n 2; c) scheme for attributes, and it is shown that the TNTVSS is more efficient.  相似文献   
1000.
Griliches and Hausman 5 Griliches, Z. and Hausman, J. A. 1986. Errors in variables in panel data. J. Econometrics, 32: 93118. [Crossref], [Web of Science ®] [Google Scholar] and Wansbeek 11 Wansbeek, T. J. 2001. GMM estimation in panel data models with measurement error. J. Econometrics, 104: 259268. [Crossref], [Web of Science ®] [Google Scholar] proposed using the generalized method of moments (GMM) to obtain consistent estimators in linear regression models for longitudinal data with measurement error in one covariate, without requiring additional validation or replicate data. For usefulness of this methodology, we must extend it to the more realistic situation where more than one covariate are measured with error. Such an extension is not straightforward, since measurement errors across different covariates may be correlated. By a careful construction of the measurement error correlation structure, we are able to extend Wansbeek's GMM and show that the extended Griliches and Hausman's GMM is equivalent to the extended Wansbeek's GMM. For illustration, we apply the extended GMM to data from two medical studies, and compare it with the naive method and the method assuming only one covariate having measurement error.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号