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   4042篇
  免费   110篇
  国内免费   18篇
管理学   201篇
民族学   9篇
人口学   56篇
丛书文集   46篇
理论方法论   31篇
综合类   528篇
社会学   56篇
统计学   3243篇
  2024年   8篇
  2023年   22篇
  2022年   34篇
  2021年   54篇
  2020年   65篇
  2019年   143篇
  2018年   185篇
  2017年   285篇
  2016年   164篇
  2015年   127篇
  2014年   167篇
  2013年   1085篇
  2012年   323篇
  2011年   139篇
  2010年   128篇
  2009年   138篇
  2008年   147篇
  2007年   106篇
  2006年   83篇
  2005年   103篇
  2004年   89篇
  2003年   69篇
  2002年   64篇
  2001年   53篇
  2000年   59篇
  1999年   50篇
  1998年   60篇
  1997年   40篇
  1996年   17篇
  1995年   27篇
  1994年   17篇
  1993年   19篇
  1992年   20篇
  1991年   9篇
  1990年   9篇
  1989年   7篇
  1988年   8篇
  1987年   5篇
  1986年   2篇
  1985年   7篇
  1984年   6篇
  1983年   7篇
  1982年   4篇
  1981年   3篇
  1980年   5篇
  1979年   1篇
  1978年   1篇
  1977年   5篇
  1975年   1篇
排序方式: 共有4170条查询结果,搜索用时 15 毫秒
81.
提高城市群土地利用TFP对合理高效利用土地资源,协调好城市群经济发展、资源配置和环境保护具有重大理论和实践意义.文章运用DEA-Malmquist指数对2003—2016年动态视角下中国城市群土地利用TFP进行测度和时空演变分析,并利用Tobit回归模型对影响城市群土地利用TFP变化的因素进行深入研究.结果表明:从时间维度看,城市群土地利用TFP年均上升0.7%,城市群土地利用TFP增长由技术效率和技术进步"双核驱动",技术效率的提升主要与纯技术效率提升有关,规模效率是技术效率和土地利用TFP提升的瓶颈约束;从空间维度看,晋中、哈长、海峡西岸、中原、长江中游、北部湾、成渝、黔中、关中平原和兰西城市群土地利用TFP呈下降趋势,其余城市群土地利用TFP均呈上升趋势,且京津冀、呼包鄂榆、辽中南、长江三角洲、山东半岛和天山北坡城市群土地利用TFP增长为技术进步和技术效率"双核驱动";从影响因素看,人均GDP和年末金融机构人民币各项贷款余额对中国城市群土地利用TFP具有正向促进作用,城市财政支出占本市GDP的比重和人口密度具有负向阻碍作用.  相似文献   
82.
The Hartley‐Rao‐Cochran sampling design is an unequal probability sampling design which can be used to select samples from finite populations. We propose to adjust the empirical likelihood approach for the Hartley‐Rao‐Cochran sampling design. The approach proposed intrinsically incorporates sampling weights, auxiliary information and allows for large sampling fractions. It can be used to construct confidence intervals. In a simulation study, we show that the coverage may be better for the empirical likelihood confidence interval than for standard confidence intervals based on variance estimates. The approach proposed is simple to implement and less computer intensive than bootstrap. The confidence interval proposed does not rely on re‐sampling, linearization, variance estimation, design‐effects or joint inclusion probabilities.  相似文献   
83.
Bridge penalized regression has many desirable statistical properties such as unbiasedness, sparseness as well as ‘oracle’. In Bayesian framework, bridge regularized penalty can be implemented based on generalized Gaussian distribution (GGD) prior. In this paper, we incorporate Bayesian bridge-randomized penalty and its adaptive version into the quantile regression (QR) models with autoregressive perturbations to conduct Bayesian penalization estimation. Employing the working likelihood of the asymmetric Laplace distribution (ALD) perturbations, the Bayesian joint hierarchical models are established. Based on the mixture representations of the ALD and generalized Gaussian distribution (GGD) priors of coefficients, the hybrid algorithms based on Gibbs sampler and Metropolis-Hasting sampler are provided to conduct fully Bayesian posterior estimation. Finally, the proposed Bayesian procedures are illustrated by some simulation examples and applied to a real data application of the electricity consumption.  相似文献   
84.
In this article, the Ridge–GME parameter estimator, which combines Ridge Regression and Generalized Maximum Entropy, is improved in order to eliminate the subjectivity in the analysis of the ridge trace. A serious concern with the visual inspection of the ridge trace to define the supports for the parameters in the Ridge–GME parameter estimator is the misinterpretation of some ridge traces, in particular where some of them are very close to the axes. A simulation study and two empirical applications are used to illustrate the performance of the improved estimator. A MATLAB code is provided as supplementary material.  相似文献   
85.
The Eurovision Song Contest is an annual musical competition held among active members of the European Broadcasting Union since 1956. The event is televised live across Europe. Each participating country presents a song and receive a vote based on a combination of tele-voting and jury. Over the years, this has led to speculations of tactical voting, discriminating against some participants and thus inducing bias in the final results. In this paper we investigate the presence of positive or negative bias (which may roughly indicate favouritisms or discrimination) in the votes based on geographical proximity, migration and cultural characteristics of the participating countries through a Bayesian hierarchical model. Our analysis found no evidence of negative bias, although mild positive bias does seem to emerge systematically, linking voters to performers.  相似文献   
86.
The recently developed rolling year GEKS procedure makes maximum use of all matches in the data to construct nonrevisable price indexes that are approximately free from chain drift. A potential weakness is that unmatched items are ignored. In this article we use imputation Törnqvist price indexes as inputs into the rolling year GEKS procedure. These indexes account for quality changes by imputing the “missing prices” associated with new and disappearing items. Three imputation methods are discussed. The first method makes explicit imputations using a hedonic regression model which is estimated for each time period. The other two methods make implicit imputations; they are based on time dummy hedonic and time-product dummy regression models and are estimated on bilateral pooled data. We present empirical evidence for New Zealand from scanner data on eight consumer electronics products and find that accounting for quality change can make a substantial difference.  相似文献   
87.
88.
In this article, we derive general matrix formulae for second-order biases of maximum likelihood estimators (MLEs) in a class of heteroscedastic symmetric nonlinear regression models, thus generalizing some results in the literature. This class of regression models includes all symmetric continuous distributions, and has a wide range of practical applications in various fields such as engineering, biology, medicine and economics, among others. The variety of distributions with different kurtosis coefficients than the normal may give more flexibility in the choice of an appropriate distribution, particularly to accommodate outlying and influential observations. We derive a joint iterative process for estimating the mean and dispersion parameters. We also present simulation studies for the biases of the MLEs.  相似文献   
89.
In this article, we consider a nonparametric regression model with replicated observations based on the dependent error’s structure, for exhibiting dependence among the units. The wavelet procedures are developed to estimate the regression function. The moment consistency, the strong consistency, strong convergence rate and asymptotic normality of wavelet estimator are established under suitable conditions. A simulation study is undertaken to assess the finite sample performance of the proposed method.  相似文献   
90.
Analysis of massive datasets is challenging owing to limitations of computer primary memory. Composite quantile regression (CQR) is a robust and efficient estimation method. In this paper, we extend CQR to massive datasets and propose a divide-and-conquer CQR method. The basic idea is to split the entire dataset into several blocks, applying the CQR method for data in each block, and finally combining these regression results via weighted average. The proposed approach significantly reduces the required amount of primary memory, and the resulting estimate will be as efficient as if the entire data set is analysed simultaneously. Moreover, to improve the efficiency of CQR, we propose a weighted CQR estimation approach. To achieve sparsity with high-dimensional covariates, we develop a variable selection procedure to select significant parametric components and prove the method possessing the oracle property. Both simulations and data analysis are conducted to illustrate the finite sample performance of the proposed methods.  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