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   26639篇
  免费   905篇
  国内免费   282篇
管理学   845篇
劳动科学   9篇
民族学   247篇
人才学   6篇
人口学   373篇
丛书文集   3077篇
理论方法论   902篇
综合类   20943篇
社会学   460篇
统计学   964篇
  2024年   23篇
  2023年   115篇
  2022年   181篇
  2021年   204篇
  2020年   268篇
  2019年   265篇
  2018年   264篇
  2017年   321篇
  2016年   419篇
  2015年   552篇
  2014年   1376篇
  2013年   1237篇
  2012年   1565篇
  2011年   1963篇
  2010年   1618篇
  2009年   1648篇
  2008年   1777篇
  2007年   2159篇
  2006年   2066篇
  2005年   1962篇
  2004年   1845篇
  2003年   1739篇
  2002年   1396篇
  2001年   1161篇
  2000年   664篇
  1999年   250篇
  1998年   129篇
  1997年   128篇
  1996年   103篇
  1995年   111篇
  1994年   83篇
  1993年   50篇
  1992年   53篇
  1991年   35篇
  1990年   28篇
  1989年   29篇
  1988年   17篇
  1987年   9篇
  1986年   5篇
  1985年   2篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1977年   1篇
排序方式: 共有10000条查询结果,搜索用时 640 毫秒
1.
Poor quality of care may have a detrimental effect on access and take-up and can become a serious barrier to the universality of health services. This consideration is of particular interest in view of the fact that health systems in many countries must address a growing public-sector deficit and respond to increasing pressures due to COVID-19 and aging population, among other factors. In line with a rapidly emerging literature, we focus on patient satisfaction as a proxy for quality of health care. Drawing on rich longitudinal and cross-sectional data for Spain and multilevel estimation techniques, we show that in addition to individual level differences, policy levers (such as public health spending and the patient-doctor ratio, in particular) exert a considerable influence on the quality of a health care system. Our results suggest that policymakers seeking to enhance the quality of care should be cautious when compromising the level of health resources, and in particular, health personnel, as a response to economic downturns in a sector that traditionally had insufficient human resources in many countries, which have become even more evident in the light of the current health crisis. Additionally, we provide evidence that the increasing reliance on the private health sector may be indicative of inefficiencies in the public system and/or the existence of features of private insurance which are deemed important by patients.  相似文献   
2.
随着信息技术的发展,数字经济已经成为经济增长的"新引擎"。但由于缺乏权威的产业统计分类标准,学者们一直面临"数字经济研究缺乏数字依据"的尴尬境地。文章基于国家统计局公布并实施的《数字经济及其核心产业统计分类(2021)》中的分类标准,对各省份统计年鉴的数据进行重新整理,利用熵权法构建数字经济发展指数,测度了我国30个省份的数字经济发展水平,分析了各省份数字经济发展的差异以及时空特征。研究发现,2009—2019年我国数字经济产业发展迅猛,各项子产业都取得了长足的进步。相比较而言,数字要素驱动业发展速度略低于其他三个子产业;数字经济发展存在着明显的区域不平衡。东中部地区的数字经济发展状况明显优于西部地区,南方优于北方,而且区域不平衡有持续扩大趋势。  相似文献   
3.
自然保护地在维持生态平衡,实现生态系统服务功能中可以发挥重要作用,但不同类型自然保护地的主导生态系统服务功能供给存在一定差异.《自然保护地法》立法工作须依赖理论上对自然保护地的类型化,并在此基础上建构对应型的规划建设、运营管理等方面的具体制度.因此,基于生态系统服务功能供给的空间差异,可以将当前相互重叠、缺乏体系的自然保护地划分为国家公园、自然保护区、自然公园、自然保护小区等四种类型,搭建"1部基础法律+4部类型化条例(或法律)"的自然保护地法律体系,并可以通过体系化公法、私法制度工具强化自然保护地的有效治理.  相似文献   
4.
建设具有中国特色、中国风格、中国气派的哲学社会科学,一直是我国哲学社会科学繁荣发展的根本目的.提升高校哲学社会科学繁荣发展水平,离不开科学有效的哲学社会科学研究评价.坚持党的领导、"二为"方向和"双百"方针是哲学社会科学繁荣发展的根本保障,坚持"质量为本"和"创新至上"是哲学社会科学繁荣发展的必然要求,坚持科学权威和公开透明是哲学社会科学研究评价的现实需要.结合当前高校哲学社会科学研究评价中"量化评价下数量与质量的关系论辩","学术评价与科研管理评价的边界异化"和"学术权力和行政权力的制度规制"三大问题聚讼,文章建议通过强化学术成果质量保障机制、优化学术共同体工作机制、构建学术争鸣长效机制和完善学术成果转化应用机制等制度建设,推动构建科学权威、公开透明的哲学社会科学研究评价体系,以期进一步改善新时代高校哲学社会科学研究评价工作.  相似文献   
5.
基于固定比例生产技术和多产品随机需求的情形,研究了联产品制造商的两阶段产量和价格联合优化模型。通过反向倒推的优化求解,得到了联产品制造商的最优产量和价格决策以及变化规律。同时研究了需求服从均匀分布时,需求波动对均衡的影响。研究结果表明,在订货成本较低和一种产品的需求波动性较大时,当另外一种产品的波动增大,则该产品的最优订货量增大,同时价格下降。借助数值仿真,分析了价格敏感度和产出比例对最优决策和利润的影响。结果表明,在给定一种产品的价格敏感度时,另外一种的价格敏感度越大,那么该产品的价格就越低,制造商的订货量就下降。当一种产品的产出比例固定时,另一种产品的产出比例上升时,则该产品的价格下降,制造商的订货量下降,总利润上升。  相似文献   
6.
目前我国农户的地权诉求已经发生了很大的变化,即由地权稳定、自主经营向农地资源的优化配置和高效利用转化。这一变化的内在动力是农户急切希望改变承包地过于细碎化以及改善农业生产经营基本条件。考察我国农地制度的发展史可以发现,我国农地制度变迁的基本逻辑就是农户的地权诉求决定农地制度的发展方向,这一点在当下一些地方的农地制度创新试验和经验中再次得到证明。今后我国农地制度创新必须遵循这一逻辑,根据我国农户地权诉求的变化,实施农户自愿前提下的承包地连片重划,争取国家对承包地重划制度的支持,强化农民集体民主决策制度,地方政府也要给予必要的支持。  相似文献   
7.
Financial stress index (FSI) is considered to be an important risk management tool to quantify financial vulnerabilities. This paper proposes a new framework based on a hybrid classifier model that integrates rough set theory (RST), FSI, support vector regression (SVR) and a control chart to identify stressed periods. First, the RST method is applied to select variables. The outputs are used as input data for FSI–SVR computation. Empirical analysis is conducted based on monthly FSI of the Federal Reserve Bank of Saint Louis from January 1992 to June 2011. A comparison study is performed between FSI based on the principal component analysis and FSI–SVR. A control chart based on FSI–SVR and extreme value theory is proposed to identify the extremely stressed periods. Our approach identified different stressed periods including internet bubble, subprime crisis and actual financial stress episodes, along with the calmest periods, agreeing with those given by Federal Reserve System reports.  相似文献   
8.
A conformance proportion is an important and useful index to assess industrial quality improvement. Statistical confidence limits for a conformance proportion are usually required not only to perform statistical significance tests, but also to provide useful information for determining practical significance. In this article, we propose approaches for constructing statistical confidence limits for a conformance proportion of multiple quality characteristics. Under the assumption that the variables of interest are distributed with a multivariate normal distribution, we develop an approach based on the concept of a fiducial generalized pivotal quantity (FGPQ). Without any distribution assumption on the variables, we apply some confidence interval construction methods for the conformance proportion by treating it as the probability of a success in a binomial distribution. The performance of the proposed methods is evaluated through detailed simulation studies. The results reveal that the simulated coverage probability (cp) for the FGPQ-based method is generally larger than the claimed value. On the other hand, one of the binomial distribution-based methods, that is, the standard method suggested in classical textbooks, appears to have smaller simulated cps than the nominal level. Two alternatives to the standard method are found to maintain their simulated cps sufficiently close to the claimed level, and hence their performances are judged to be satisfactory. In addition, three examples are given to illustrate the application of the proposed methods.  相似文献   
9.
Researchers have been developing various extensions and modified forms of the Weibull distribution to enhance its capability for modeling and fitting different data sets. In this note, we investigate the potential usefulness of the new modification to the standard Weibull distribution called odd Weibull distribution in income economic inequality studies. Some mathematical and statistical properties of this model are proposed. We obtain explicit expressions for the first incomplete moment, quantile function, Lorenz and Zenga curves and related inequality indices. In addition to the well-known stochastic order based on Lorenz curve, the stochastic order based on Zenga curve is considered. Since the new generalized Weibull distribution seems to be suitable to model wealth, financial, actuarial and especially income distributions, these findings are fundamental in the understanding of how parameter values are related to inequality. Also, the estimation of parameters by maximum likelihood and moment methods is discussed. Finally, this distribution has been fitted to United States and Austrian income data sets and has been found to fit remarkably well in compare with the other widely used income models.  相似文献   
10.
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