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   1240篇
  免费   39篇
  国内免费   61篇
化学   43篇
晶体学   11篇
力学   22篇
综合类   26篇
数学   1132篇
物理学   106篇
  2024年   9篇
  2023年   9篇
  2022年   19篇
  2021年   26篇
  2020年   23篇
  2019年   20篇
  2018年   23篇
  2017年   40篇
  2016年   44篇
  2015年   21篇
  2014年   46篇
  2013年   114篇
  2012年   51篇
  2011年   56篇
  2010年   59篇
  2009年   94篇
  2008年   63篇
  2007年   58篇
  2006年   49篇
  2005年   55篇
  2004年   32篇
  2003年   30篇
  2002年   41篇
  2001年   28篇
  2000年   35篇
  1999年   20篇
  1998年   24篇
  1997年   22篇
  1996年   18篇
  1995年   14篇
  1994年   27篇
  1993年   17篇
  1992年   13篇
  1991年   9篇
  1990年   12篇
  1989年   11篇
  1988年   12篇
  1987年   10篇
  1986年   8篇
  1985年   13篇
  1984年   10篇
  1982年   8篇
  1981年   6篇
  1980年   6篇
  1979年   7篇
  1978年   10篇
  1977年   3篇
  1975年   3篇
  1974年   3篇
  1973年   3篇
排序方式: 共有1340条查询结果,搜索用时 0 毫秒
51.
In a variety of statistical problems one needs to solve an equation in order to get an estimator. We consider the large sample properties of such estimators generated from samples that are not necessarily identically distributed. Very general assumptions that lead to the existence, strong consistency, and asymptotic normality of the estimators are given. A number of results that are useful in verifying the general assumptions are given and an example illustrates their use. General applications to maximum likelihood, iteratively reweighted least squares, and robust estimation are discussed briefly.  相似文献   
52.
This paper considers variable selection for moment restriction models.We propose a penalized empirical likelihood(PEL) approach that has desirable asymptotic properties comparable to the penalized likelihood approach,which relies on a correct parametric likelihood specification.In addition to being consistent and having the oracle property,PEL admits inference on parameter without having to estimate its estimator's covariance.An approximate algorithm,along with a consistent BIC-type criterion for selecting ...  相似文献   
53.
在Binomial模型中考虑over-dispersion时,每一个独立事件成功的概率通常被视为一个连续随机变量.在本文中,我们提出了成功概率服从Kumaraswamy分布的混合Binomial模型.讨论了这个模型的随机序和相依性;并用数据来拟合这些模型,数值计算结果表明在拟合某些数据时KB模型比BB模型拟合效果更好.  相似文献   
54.
关于随机选择的一个强极限定理   总被引:1,自引:0,他引:1  
本文利用似然比和区间剖分法研究相依N值随机变量序列选择的极限性质,得到关于赌博方法的一个强极限定理的若干推广。  相似文献   
55.
In this paper we investigate some aspects like estimation and hypothesis testing in the simple structural regression model with measurement errors. Use is made of orthogonal parametrizations obtained in the literature. Emphasis is placed on some properties of the maximum likelihood estimators and also on the distribution of the likelihood ratio statistics.  相似文献   
56.
Adaptive anisotropic noise filtering for magnitude MR data   总被引:4,自引:0,他引:4  
Conventional noise filtering schemes applied to magnitude magnetic resonance (MR) images tacitly assume Gauss distributed noise. Magnitude MR data, however, are Rice distributed. Not incorporating this knowledge leads inevitably to biased results, in particular when applying such filters in regions with low signal-to-noise ratio. In this work, we show how the Rice data probability distribution can be incorporated so as to construct a noise filter that is far less biased.  相似文献   
57.
    
This article proposes the application of the maximum-entropy principle (MEP) to agency contracting (where a principal hires an agent to make decisions on their behalf) in situations where the principal and agent only have partial knowledge on the probability distribution of the output conditioned on the agent’s actions. The paper characterizes the second-best agency contract from a maximum entropy distribution (MED) obtained from applying the MEP to the agency situation consistently with the information available. We show that, with the minimum shared information about the output distribution for the agency relationship to take place, the second-best compensation contract is (a monotone transformation of) an increasing affine function of output. With additional information on the output distribution, the second-best optimal contracts can be more complex. The second-best contracts obtained theoretically from the MEP cover many compensation schemes observed in real agency relationships.  相似文献   
58.
    
The point and interval estimations for the unknown parameters of an exponentiated half-logistic distribution based on adaptive type II progressive censoring are obtained in this article. At the beginning, the maximum likelihood estimators are derived. Afterward, the observed and expected Fisher’s information matrix are obtained to construct the asymptotic confidence intervals. Meanwhile, the percentile bootstrap method and the bootstrap-t method are put forward for the establishment of confidence intervals. With respect to Bayesian estimation, the Lindley method is used under three different loss functions. The importance sampling method is also applied to calculate Bayesian estimates and construct corresponding highest posterior density (HPD) credible intervals. Finally, numerous simulation studies are conducted on the basis of Markov Chain Monte Carlo (MCMC) samples to contrast the performance of the estimations, and an authentic data set is analyzed for exemplifying intention.  相似文献   
59.
    
In this paper, we study the phase transition property of an Ising model defined on a special random graph—the stochastic block model (SBM). Based on the Ising model, we propose a stochastic estimator to achieve the exact recovery for the SBM. The stochastic algorithm can be transformed into an optimization problem, which includes the special case of maximum likelihood and maximum modularity. Additionally, we give an unbiased convergent estimator for the model parameters of the SBM, which can be computed in constant time. Finally, we use metropolis sampling to realize the stochastic estimator and verify the phase transition phenomenon thfough experiments.  相似文献   
60.
    
This paper states that most commonly used minimum divergence estimators are MLEs for suited generalized bootstrapped sampling schemes. Optimality in the sense of Bahadur for associated tests of fit under such sampling is considered.  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