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   3030篇
  免费   180篇
  国内免费   63篇
管理学   532篇
劳动科学   4篇
民族学   28篇
人才学   1篇
人口学   28篇
丛书文集   303篇
理论方法论   85篇
综合类   2035篇
社会学   44篇
统计学   213篇
  2024年   26篇
  2023年   72篇
  2022年   90篇
  2021年   80篇
  2020年   90篇
  2019年   75篇
  2018年   84篇
  2017年   78篇
  2016年   87篇
  2015年   124篇
  2014年   236篇
  2013年   218篇
  2012年   256篇
  2011年   276篇
  2010年   218篇
  2009年   199篇
  2008年   172篇
  2007年   174篇
  2006年   147篇
  2005年   105篇
  2004年   94篇
  2003年   87篇
  2002年   68篇
  2001年   48篇
  2000年   39篇
  1999年   28篇
  1998年   18篇
  1997年   17篇
  1996年   14篇
  1995年   12篇
  1994年   9篇
  1993年   5篇
  1992年   8篇
  1991年   5篇
  1990年   4篇
  1989年   3篇
  1988年   4篇
  1987年   3篇
排序方式: 共有3273条查询结果,搜索用时 31 毫秒
91.
In this article, a new algorithm for rather expensive simulation problems is presented, which consists of two phases. In the first phase, as a model-based algorithm, the simulation output is used directly in the optimization stage. In the second phase, the simulation model is replaced by a valid metamodel. In addition, a new optimization algorithm is presented. To evaluate the performance of the proposed algorithm, it is applied to the (s,S) inventory problem as well as to five test functions. Numerical results show that the proposed algorithm leads to better solutions with less computational time than the corresponding metamodel-based algorithm.  相似文献   
92.
上海的人口总量和结构一直与其独特的工业化、城镇化进程密不可分。工业化带动人口发展,人口发展推动城市发展。改革开放以来,上海正处于第四波工业化时期,人口增长较快。在人口结构上,户籍人口老龄化,而外来人口具有就近流动、城城流动、定居化特点,且教育水平逐年提高。从承载力上看,上海人口总量合理,但人口分布的不合理影响了人口结构的发展、城市社会的融合,带来了核心区人口过密、产城融合不畅的问题,以及偏好"人脑"、排斥"人手"的问题。面对人口老龄化和可能的人口逆流,上海应稳定人口总量,建设整体推进的多中心发展人口分布格局,完善户籍制度改革,破解"新二元结构",推动社会保障和公共服务均等化,同时结合政府改革,完善相关配套改革措施。  相似文献   
93.
全球治理的提出源于全球化的推动,而全球治理的提出及实践则使国际行政法的产生、形成成为可能。具体而言,全球公民社会的兴起与国际非政府组织的发展是国际行政法产生的两个现实驱动因素。国际行政法的产生路径可总结为"自下而上"和"自上而下"的路径。国际行政法具有区别于国内行政法的若干明显特征,国际层面相比国内层面的很多特殊性也使得国际行政法的体系化发展面临诸多挑战。这些问题虽然不能忽视,但它们也并非不可克服。虽然国际行政法不如国内行政法成熟,但是如能改进合法性,便能够将超国家机构的全球治理职能发挥得更好。全球治理语境下国际行政法体系的产生、形成是一种历史的必然趋势。  相似文献   
94.
We propose a new procedure for the multinomial selection problem to solve a real problem of any modern Air Force: the elaboration of better air-to-air tactics for Beyond Visual Range air-to-air combat that maximize its aircraft survival probability H(θ, ω), as well as enemy aircraft downing probability G(θ, ω). In this study, using a low-resolution simulator with generic parameters for the aircraft and missiles, we could increase an average success rate of 16.69% and 16.23% for H(θ, ω) and G(θ, ω), respectively, to an average success rate of 76.85% and 79.30%. We can assure with low probability of being wrong that the selected tactic has greater probability of yielding greater success rates in both H(θ, ω) and G(θ, ω) than any simulated tactic.  相似文献   
95.
We propose a shift in emphasis when communicating to people when the objective is to motivate household disaster preparedness actions. This shift is to emphasize the communication of preparedness actions (what to do about risk) rather than risk itself. We have called this perspective “communicating actionable risk,” and it is grounded in diffusion of innovations and communication theories. A representative sample of households in the nation was analyzed using a path analytic framework. Preparedness information variables (including content, density, and observation), preparedness mediating variables (knowledge, perceived effectiveness, and milling), and preparedness actions taken were modeled. Clear results emerged that provide a strong basis for communicating actionable risk, and for the conclusion both that information observed (seeing preparedness actions that other have taken) and information received (receiving recommendations about what preparedness actions to take) play key, although different, roles in motivating preparedness actions among the people in our nation.  相似文献   
96.
作为当今公共政策研究领域最炙手可热的理论模型之一,约翰·金登的多源流分析理论业已得到国内外学者的广泛应用与认可。在对该模型的相关内容进行简单铺陈后,通过辨析国内外不同的政策主体参与逻辑,进一步厘清了我国公共决策的独有特征。研究重点是在整合提炼西方既有修正思路的基础上,沿袭模型的模糊性假设,结合我国具体实践案例,对多源流模型进行优化与补充。研究表明,中国决策情境下的多源流模型优化主要有提高源流间的融合性、政治源流的核心化、焦点事件的独立化以及特殊情况下的临时决策等四种路径,四种优化与补充路径的有机结合将为进一步提升模型适用性提供帮助。  相似文献   
97.
In this study, a new method for the estimation of the shrinkage and biasing parameters of Liu-type estimator is proposed. Because k is kept constant and d is optimized in Liu’s method, a (k, d) pair is not guaranteed to be the optimal point in terms of the mean square error of the parameters. The optimum (k, d) pair that minimizes the mean square error, which is a function of the parameters k and d, should be estimated through a simultaneous optimization process rather than through a two-stage process. In this study, by utilizing a different objective function, the parameters k and d are optimized simultaneously with the particle swarm optimization technique.  相似文献   
98.
This article modifies two internal validity measures and applies them to evaluate the quality of clustering for probability density functions (pdfs). Based on these measures, we propose a new modified genetic algorithm called GA-CDF to establish the suitable clusters for pdfs. The proposed algorithm is tested by four numerical examples including two synthetic data sets and two real data sets. These examples illustrate the superiority of proposed algorithm over some existing algorithms in evaluating the internal or external validity measures. It demonstrates the feasibility and applicability of the GA-CDF for practical problems in data mining.  相似文献   
99.
Maximin distance designs are useful for conducting expensive computer experiments. In this article, we compare some global optimization algorithms for constructing such designs. We also introduce several related space-filling designs, including nested maximin distance designs, sliced maximin distance designs, and general maximin distance designs with better projection properties. These designs possess more flexible structures than their analogs in the literature. Examples of these designs constructed by the algorithms are presented.  相似文献   
100.
采矿工程专业人才培养方案优化与实践   总被引:1,自引:0,他引:1  
随着全球经济一体化的发展,我国煤炭行业得到了快速发展,煤炭工业需要大量的高素质复合型采矿工程专业毕业生,因此,修订和完善采矿专业人才培养方案具有重要意义。河南理工大学采矿工程专业为了不断提高人才培养质量,对采矿工程专业人才培养方案进行了优化,2010年10月通过全国工程教育专家委员会的认证工作。新的人才培养方案已经得到实施,效果明显。  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