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   3217篇
  免费   115篇
  国内免费   39篇
管理学   259篇
劳动科学   2篇
民族学   20篇
人口学   178篇
丛书文集   166篇
理论方法论   102篇
综合类   1530篇
社会学   61篇
统计学   1053篇
  2024年   3篇
  2023年   14篇
  2022年   22篇
  2021年   34篇
  2020年   66篇
  2019年   60篇
  2018年   91篇
  2017年   124篇
  2016年   88篇
  2015年   74篇
  2014年   144篇
  2013年   444篇
  2012年   210篇
  2011年   194篇
  2010年   156篇
  2009年   166篇
  2008年   187篇
  2007年   202篇
  2006年   172篇
  2005年   179篇
  2004年   127篇
  2003年   123篇
  2002年   106篇
  2001年   89篇
  2000年   60篇
  1999年   41篇
  1998年   33篇
  1997年   31篇
  1996年   22篇
  1995年   27篇
  1994年   14篇
  1993年   11篇
  1992年   11篇
  1991年   15篇
  1990年   9篇
  1989年   4篇
  1988年   5篇
  1987年   2篇
  1986年   2篇
  1985年   1篇
  1984年   3篇
  1982年   4篇
  1979年   1篇
排序方式: 共有3371条查询结果,搜索用时 390 毫秒
71.
制造业是我国国民经济的支柱产业,但也是环境污染物排放的主要来源、能源消耗主体和温室气体排放大户。制造系统高能耗、高物耗、高碳排放的加工过程是造成制造业碳排放量大的重要原因。生产单元作为制造系统的加工的主体,其碳排放量的核算是确定整个制造系统乃至制造业碳排放总量的关键。本文首先对生产单元的原材料、电能、辅助物料及废屑处理所引起的碳排放进行分析,确定生产单元的碳排放源;其次,产品合格率的不同会造成生产单元输入及输出的成品/半成品数量的差异,进而影响生产单元单位产品的碳排放量,在此基础上,综合考虑了原材料、电能、辅助物料及废屑处理的碳排放情况,构建了给定工艺流程下生产单元碳排放核算模型。最后,结合一汽车排气装置加工实例,分别核算加工过程中九个生产单元的碳排放量,验证了模型的可行性。  相似文献   
72.
文章选取初次分配工资分配率、城镇居民基尼系数、各收入阶层旅游消费占比作为分析指标,经分析研究所得结论为:低、中收入阶层旅游消费占比与分配率负相关,分配率所代表的初次收入分配总量性影响对中收入阶层旅游消费影响较大,中、高收入阶层旅游消费占比都与城镇居民基尼系数正相关,其中城镇居民基尼系数代表的初次收入分配结构性影响对高收入阶层旅游消费影响较大;并针对各阶层的特殊性对各收入阶层旅游消费发展提出相应政策建议.  相似文献   
73.
In this article, we calibrate the Vasicek interest rate model under the risk neutral measure by learning the model parameters using Gaussian processes for machine learning regression. The calibration is done by maximizing the likelihood of zero coupon bond log prices, using mean and covariance functions computed analytically, as well as likelihood derivatives with respect to the parameters. The maximization method used is the conjugate gradients. The only prices needed for calibration are zero coupon bond prices and the parameters are directly obtained in the arbitrage free risk neutral measure.  相似文献   
74.
Methods are proposed to combine several individual classifiers in order to develop more accurate classification rules. The proposed algorithm uses Rademacher–Walsh polynomials to combine M (≥2) individual classifiers in a nonlinear way. The resulting classifier is optimal in the sense that its misclassification error rate is always less than, or equal to, that of each constituent classifier. A number of numerical examples (based on both real and simulated data) are also given. These examples demonstrate some new, and far-reaching, benefits of working with combined classifiers.  相似文献   
75.
Maryam Esna-Ashari 《Statistics》2016,50(6):1421-1433
In survival analysis and reliability theory, a fundamental problem is the study of lifetime properties of a live organism or system. In this regard, there have been considered and studied several models based on different concepts of ageing such as hazard rate and mean residual life. In this paper, we consider an additive-multiplicative hazard model (AMHM) and study some reliability and ageing properties of the proposed model. We then specify the bivariate models whose conditionals satisfy AMHM. Several properties of the proposed bivariate model are investigated and adequacy of the model is evaluated based on a real data set.  相似文献   
76.
Motivated by the need to analyze the National Longitudinal Surveys data, we propose a new semiparametric longitudinal mean‐covariance model in which the effects on dependent variable of some explanatory variables are linear and others are non‐linear, while the within‐subject correlations are modelled by a non‐stationary autoregressive error structure. We develop an estimation machinery based on least squares technique by approximating non‐parametric functions via B‐spline expansions and establish the asymptotic normality of parametric estimators as well as the rate of convergence for the non‐parametric estimators. We further advocate a new model selection strategy in the varying‐coefficient model framework, for distinguishing whether a component is significant and subsequently whether it is linear or non‐linear. Besides, the proposed method can also be employed for identifying the true order of lagged terms consistently. Monte Carlo studies are conducted to examine the finite sample performance of our approach, and an application of real data is also illustrated.  相似文献   
77.
This article examined the theoretical meanings of pension rights and analyzed their effects on women's economic risks in developed countries. First, based on the status of a citizen, worker, parent, and spouse, this study investigated how pension benefits are guaranteed as a citizen regardless of work history, the degree to which women's disadvantageous situations in the labor market and unpaid work are compensated by public pension as workers and parents, and how marital status is treated in the different pension systems. Second, analysis of the effect of pension rights showed that individual rights is a significant factor to prevent economic risks of elderly women. Derived rights did not seem to secure the economic welfare of elderly women, at least in a comparative context. This finding suggested that developing individual rights, rather than derived rights, is the way to guarantee long‐term elderly women's economic welfare.  相似文献   
78.
韦森 《科学发展》2014,(2):26-29
从经济的投资、消费和出口数据看,中国经济增速确实在下行。为了保持中国经济8%的增速,我们已付出了很高的代价;经过35年的高速增长,在各行各业产能基本过剩的情况下,中国经济增速正在下移。观察1950年代后日本、中国台湾和香港地区经济发展的过程,其经济高速增长后,也是一个台阶又一个台阶地下来。中国不能再靠高投资来推动经济增长。  相似文献   
79.
80.
Abstract

In this paper we find the maximum likelihood estimates (MLEs) of hazard rate and mean residual life functions (MRLF) of Pareto distribution, their asymptotic non degenerate distribution, exact distribution and moments. We also discuss the uniformly minimum variance unbiased estimate (UMVUE) of hazard rate function and MRLF. Finally, two numerical examples with simulated data and real data set, are presented to illustrate the proposed estimates.  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