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   7001篇
  免费   229篇
  国内免费   90篇
管理学   734篇
民族学   32篇
人才学   1篇
人口学   49篇
丛书文集   506篇
理论方法论   272篇
综合类   3578篇
社会学   366篇
统计学   1782篇
  2024年   14篇
  2023年   72篇
  2022年   91篇
  2021年   119篇
  2020年   132篇
  2019年   169篇
  2018年   199篇
  2017年   259篇
  2016年   163篇
  2015年   174篇
  2014年   367篇
  2013年   931篇
  2012年   455篇
  2011年   436篇
  2010年   318篇
  2009年   356篇
  2008年   363篇
  2007年   405篇
  2006年   366篇
  2005年   391篇
  2004年   348篇
  2003年   296篇
  2002年   207篇
  2001年   200篇
  2000年   136篇
  1999年   68篇
  1998年   49篇
  1997年   43篇
  1996年   34篇
  1995年   23篇
  1994年   12篇
  1993年   16篇
  1992年   26篇
  1991年   16篇
  1990年   9篇
  1989年   10篇
  1988年   7篇
  1987年   4篇
  1986年   4篇
  1985年   7篇
  1984年   1篇
  1983年   8篇
  1982年   4篇
  1981年   3篇
  1980年   3篇
  1979年   2篇
  1978年   2篇
  1977年   1篇
  1975年   1篇
排序方式: 共有7320条查询结果,搜索用时 390 毫秒
101.
农户的绿色生产技术采纳不仅有利于粮食安全和生态环境保护,而且对农业的绿色生产转型具有重要意义,农产品的电商销售可成为农户进行绿色生产的可能路径。利用有序Logit模型测度电商参与对猕猴桃种植户绿色生产技术采纳程度的影响,使用结构方程模型中的均数方差调整加权最小二乘法 (WLSMV) 和 Bootstrap 法检验技术认知的中介效应,采用倾向得分匹配法对电商参与影响农户绿色生产技术采纳程度进行稳健性检验。研究发现:电商参与显著提高了猕猴桃种植户绿色生产技术的采纳程度,并且技术认知在此过程中起着积极的中介作用。政府应从加大宣传力度、提供技术和政策支持、提高农户绿色生产技术认知等方面提高农户绿色生产技术采纳程度。  相似文献   
102.
在梳理绿色金融与产业绿色发展的耦合机理的基础上,构建耦合协调度模型,利用长江经济带九省二市2012—2017年数据,分析长江经济带各省市绿色金融与产业绿色发展耦合协调关系。研究发现:第一,长江经济带绿色金融促进产业绿色发展,产业绿色发展反哺绿色金融成效显著,二者已达到良性共振耦合,耦合协调度不断提高,发展阶段经历了勉强协调、初级协调、中级阶段到良好协调,并向着优质协调靠拢;第二,上游地区产业绿色发展已形成了区域内合作机制,产业绿色发展迅速,绿色金融与产业绿色发展耦合协调度自2012年以来上升最快;第三,九省二市绿色金融与产业绿色发展的基础和侧重点不同,二者耦合协调度呈现一定差异,但都达到了良好协调阶段。针对长江经济带绿色金融和产业绿色发展二者耦合协调度现状,提出了相应的对策建议。  相似文献   
103.
Dynamic reliability models with conditional proportional hazards   总被引:1,自引:0,他引:1  
A dynamic approach to the stochastic modelling of reliability systems is further explored. This modelling approach is particularly appropriate for load-sharing, software reliability, and multivariate failure-time models, where component failure characteristics are affected by their degree of use, amount of load, or extent of stresses experienced. This approach incorporates the intuitive notion that when a set of components in a coherent system fail at a certain time, there is a jump from one structure function to another which governs the residual lifetimes of the remaining functioning components, and since the component lifetimes are intrinsically affected by the structure function which they constitute, then at such a failure time there should also be a jump in the stochastic structure of the lifetimes of the remaining components. For such dynamically-modelled systems, the stochastic characteristics of their jump times are studied. These properties of the jump times allow us to obtain the properties of the lifetime of the system. In particular, for a Markov dynamic model, specific expressions for the exact distribution functions of the jump times are obtained for a general coherent system, a parallel system, and a series-parallel system. We derive a new family of distribution functions which describes the distributions of the jump times for a dynamically-modelled system.  相似文献   
104.
讨论了多维非退化扩散过程样本轨道的性质,得到了其极性的充分条件  相似文献   
105.
A K -sample testing problem is studied for multivariate counting processes with time-dependent frailty. Asymptotic distributions and efficiency of a class of non-parametric test statistics are established for certain local alternatives. The concept of efficiency is to show that for every non-parametric test in this class, there is a parametric submodel for which the optimal test has the same asymptotic power as the non-parametric one. The theory is applied to analyse a diabetic retinopathy study data set. A simulation study is also presented to illustrate the theory  相似文献   
106.
In electrical engineering, circuit designs are now often optimized via circuit simulation computer models. Typically, many response variables characterize the circuit's performance. Each response is a function of many input variables, including factors that can be set in the engineering design and noise factors representing manufacturing conditions. We describe a modelling approach which is appropriate for the simulator's deterministic input–output relationships. Non-linearities and interactions are identified without explicit assumptions about the functional form. These models lead to predictors to guide the reduction of the ranges of the designable factors in a sequence of experiments. Ultimately, the predictors are used to optimize the engineering design. We also show how a visualization of the fitted relationships facilitates an understanding of the engineering trade-offs between responses. The example used to demonstrate these methods, the design of a buffer circuit, has multiple targets for the responses, representing different trade-offs between the key performance measures.  相似文献   
107.
主要探讨了NFCAPP系统中工序图生成的原理、方法、工序图数据的存贮结构及工序图的输出.  相似文献   
108.
This paper is concerned with the organizationalchange and project management issues raised by theimplementation of a business process re-engineering(BPR) approach in the politicized hospital context. This is a report of research in progress,focusing on the issues arising at the problem definitionand project planning stages of a BPR application in anoperating theaters department experiencing problems with scheduling and delays. The research designrelies on a case study approach, with the researcher asparticipant observer, as both an adviser to the projectteam and as field interviewer. The paper argues that an ambitious BPR agenda is compromised inat least two regards. First, the lack of precisionsurrounding the focus and methodology of BPR givespolitically motivated actors considerable influence with respect to defining terms of reference in wayswhich will shape potential outcomes in their favor.Second, the complexity and indeterminacy of the businessprocess or patient trail can also diluteredesign attempts. The principal limitations of theapproach thus concern the impracticality of embarking onrapid and radical change working from a blanksheet of paper with respect to organizational and job design. BPR, unlike other organizationdevelopment interventions, is not a contextsensitive approach. The role of project manageris critical in establishing a working balance betweenindividual, occupational, and organizational goals in a manner perceivedto be legitimate in the context. Effective BPR projectmanagement thus requires a combination of political andprocess analysis skills. The principal opportunities of BPR derive from its process orientation,which brings a fresh perspective to a traditionally andfunctionally fragmented organizational setting, andwhich presents a potentially valuable platform for anevolutionary approach to process improvement.  相似文献   
109.
Consider the process with, cf. (1.2) on page 265 in B1, X1, …, XN a sample from a distribution F and, for i = 1, …, N, R |x 1 , - q 1 ø| , the rank of |X1 - q1ø| among |X1 - q1ø|, …, |XN - qNø|. It is shown that, under certain regularity conditions on F and on the constants pi and qi, TøN(t) is asymptotically approximately a linear function of ø uniformly in t and in ø for |ø| ≤ C. The special case where the pi and the qi, are independent of i is considered.  相似文献   
110.
基于工作流的企业业务过程集成建模方法   总被引:1,自引:0,他引:1  
工作流管理是一种对业务过程进行支持、控制、监视和优化的先进工具. 将生产制造过程 BOM和Petri 网技术应用于企业业务过程,对于相关定义、建模分析以及从BOM到Petri 网的映 射实现算法进行了说明;对基于BOM- Petri 的建模方法进行了扩展优化;最后结合算法进行了 仿真研究.  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