全文获取类型
收费全文 | 2539篇 |
免费 | 65篇 |
国内免费 | 44篇 |
专业分类
管理学 | 458篇 |
民族学 | 3篇 |
人口学 | 3篇 |
丛书文集 | 79篇 |
理论方法论 | 13篇 |
综合类 | 959篇 |
社会学 | 18篇 |
统计学 | 1115篇 |
出版年
2024年 | 9篇 |
2023年 | 16篇 |
2022年 | 43篇 |
2021年 | 26篇 |
2020年 | 37篇 |
2019年 | 70篇 |
2018年 | 74篇 |
2017年 | 128篇 |
2016年 | 81篇 |
2015年 | 75篇 |
2014年 | 82篇 |
2013年 | 327篇 |
2012年 | 166篇 |
2011年 | 117篇 |
2010年 | 106篇 |
2009年 | 93篇 |
2008年 | 129篇 |
2007年 | 143篇 |
2006年 | 136篇 |
2005年 | 125篇 |
2004年 | 113篇 |
2003年 | 83篇 |
2002年 | 71篇 |
2001年 | 64篇 |
2000年 | 72篇 |
1999年 | 56篇 |
1998年 | 39篇 |
1997年 | 29篇 |
1996年 | 30篇 |
1995年 | 22篇 |
1994年 | 17篇 |
1993年 | 10篇 |
1992年 | 24篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 10篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1981年 | 2篇 |
排序方式: 共有2648条查询结果,搜索用时 15 毫秒
201.
Junlong Zhao 《统计学通讯:模拟与计算》2015,44(6):1612-1640
In high-dimensional setting, componentwise L2boosting has been used to construct sparse model that performs well, but it tends to select many ineffective variables. Several sparse boosting methods, such as, SparseL2Boosting and Twin Boosting, have been proposed to improve the variable selection of L2boosting algorithm. In this article, we propose a new general sparse boosting method (GSBoosting). The relations are established between GSBoosting and other well known regularized variable selection methods in the orthogonal linear model, such as adaptive Lasso, hard thresholds, etc. Simulation results show that GSBoosting has good performance in both prediction and variable selection. 相似文献
202.
Jie Yang 《统计学通讯:模拟与计算》2015,44(9):2264-2277
Generalized linear models (GLMs) have been used widely for modeling the mean response both for discrete and continuous random variables with an emphasis on categorical response. Recently Yang, Mandal and Majumdar (2013) considered full factorial and fractional factorial locally D-optimal designs for binary response and two-level experimental factors. In this article, we extend their results to a general setup with response belonging to a single-parameter exponential family and for multilevel predictors. 相似文献
203.
酶是一类具有催化功能的蛋白质,对其结构和功能的研究是非常有必要的。特殊模体β-发夹是一种简单的超二级结构,它们包含了丰富的折叠信息,对酶中β-发夹的预测有助于酶结构和功能的预测。本文建立了非冗余的β-发夹模体数据集,包含1080条酶蛋白质链,2818个β-发夹模体,1098个非β-发夹。提取位点亲疏水组分及位点亲疏水紧邻关联组分作为参数,运用矩阵打分算法得到的预测结果不理想。将位点亲疏水、位点亲疏水紧邻关联组分为参数得到的打分值和平均化学位移值共同作为特征参数,输入支持向量机算法对模体进行预测,5交叉检验预测总精度是81.8%,相关系数达到了0.636。 相似文献
204.
对萧统《文选序》“事出于沉思,义归乎翰藻”的理解历史上多有不同。尤其是“义”的内涵问题,一直缺乏明确的解释。其实,这个“义”是中古文献中经常提到的“文义”之“义”,是当时文人重要的学术才能修养,它是玄学所关涉的经典和对这些经典要旨的领会与清谈的一个总称。义的表达手段主要是清谈,而清谈除了有口谈,还有笔谈或是为谈论准备下的文字资料及记录,“义归乎翰藻”之“义”,正是这些文字资料的代表,而非一般性的“意义”或者朱自清所云的典事。 相似文献
205.
刘浩 《湖南人文科技学院学报》2014,(2):129-132
安全有效的路由算法是P2P网络的关键技术之一.针对目前大多数P2P路由算法没有考虑安全性问题,并且采用随机选择下一跳节点的方法会降低路由效率,给出了一种新的P2P安全路由算法.该算法采用信任度与路径可靠性指导下一跳节点的选择,以建立安全有效的路由路径,并且引入加密、多路径传输等方法以抑制篡改、窃听等典型攻击.模拟实验结果表明,该路由算法的路由效率要优于Gnutella,安全性能好. 相似文献
206.
Shwetank Lall Seema Jaggi Cini Varghese Arpan Bhowmik 《Journal of Statistical Computation and Simulation》2018,88(6):1191-1199
In this paper, locally D-optimal saturated designs for a logistic model with one and two continuous input variables have been constructed by modifying the famous Fedorov exchange algorithm. A saturated design not only ensures the minimum number of runs in the design but also simplifies the row exchange computation. The basic idea is to exchange a design point with a point from the design space. The algorithm performs the best row exchange between design points and points form a candidate set representing the design space. Naturally, the resultant designs depend on the candidate set. For gain in precision, intuitively a candidate set with a larger number of points and the low discrepancy is desirable, but it increases the computational cost. Apart from the modification in row exchange computation, we propose implementing the algorithm in two stages. Initially, construct a design with a candidate set of affordable size and then later generate a new candidate set around the points of design searched in the former stage. In order to validate the optimality of constructed designs, we have used the general equivalence theorem. Algorithms for the construction of optimal designs have been implemented by developing suitable codes in R. 相似文献
207.
In this paper, we present an algorithm for clustering based on univariate kernel density estimation, named ClusterKDE. It consists of an iterative procedure that in each step a new cluster is obtained by minimizing a smooth kernel function. Although in our applications we have used the univariate Gaussian kernel, any smooth kernel function can be used. The proposed algorithm has the advantage of not requiring a priori the number of cluster. Furthermore, the ClusterKDE algorithm is very simple, easy to implement, well-defined and stops in a finite number of steps, namely, it always converges independently of the initial point. We also illustrate our findings by numerical experiments which are obtained when our algorithm is implemented in the software Matlab and applied to practical applications. The results indicate that the ClusterKDE algorithm is competitive and fast when compared with the well-known Clusterdata and K-means algorithms, used by Matlab to clustering data. 相似文献
208.
In this article, to reduce computational load in performing Bayesian variable selection, we used a variant of reversible jump Markov chain Monte Carlo methods, and the Holmes and Held (HH) algorithm, to sample model index variables in logistic mixed models involving a large number of explanatory variables. Furthermore, we proposed a simple proposal distribution for model index variables, and used a simulation study and real example to compare the performance of the HH algorithm with our proposed and existing proposal distributions. The results show that the HH algorithm with our proposed proposal distribution is a computationally efficient and reliable selection method. 相似文献
209.
The estimation of the mixtures of regression models is usually based on the normal assumption of components and maximum likelihood estimation of the normal components is sensitive to noise, outliers, or high-leverage points. Missing values are inevitable in many situations and parameter estimates could be biased if the missing values are not handled properly. In this article, we propose the mixtures of regression models for contaminated incomplete heterogeneous data. The proposed models provide robust estimates of regression coefficients varying across latent subgroups even under the presence of missing values. The methodology is illustrated through simulation studies and a real data analysis. 相似文献
210.
Yi Zhang 《统计学通讯:理论与方法》2018,47(2):415-426
In this article, we propose the non parametric mixture of strictly monotone regression models. For implementation, a two-step procedure is derived. We further establish the asymptotic normality of the resultant estimator and demonstrate its good performance through numerical examples. 相似文献