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   1996篇
  免费   85篇
  国内免费   36篇
财政金融   57篇
工业经济   148篇
计划管理   824篇
经济学   275篇
综合类   160篇
运输经济   48篇
旅游经济   47篇
贸易经济   198篇
农业经济   143篇
经济概况   217篇
  2024年   4篇
  2023年   21篇
  2022年   36篇
  2021年   39篇
  2020年   51篇
  2019年   38篇
  2018年   34篇
  2017年   44篇
  2016年   45篇
  2015年   70篇
  2014年   150篇
  2013年   149篇
  2012年   178篇
  2011年   209篇
  2010年   159篇
  2009年   139篇
  2008年   151篇
  2007年   177篇
  2006年   121篇
  2005年   106篇
  2004年   59篇
  2003年   42篇
  2002年   19篇
  2001年   20篇
  2000年   16篇
  1999年   6篇
  1998年   8篇
  1997年   4篇
  1996年   5篇
  1995年   3篇
  1994年   2篇
  1993年   3篇
  1992年   3篇
  1991年   3篇
  1990年   1篇
  1988年   1篇
  1982年   1篇
排序方式: 共有2117条查询结果,搜索用时 31 毫秒
1.
Additive manufacturing (AM) appears to be a particularly attractive use case for blockchain. This research combines inductive in‐depth interviews with the Delphi method to explore what potentials blockchain technology in AM creates, which adoption barriers firms need to overcome, and how supply chains will be affected by the integration of these two potentially disruptive technologies. The results suggest opportunities that are related to intellectual property (IP) rights management, the monitoring of printed parts throughout their lifecycle, process improvements, and data security. The most important barriers for blockchain adoption in AM are an absence of blockchain‐skilled specialists on the labor market, missing governance mechanisms, and a lack of firm‐internal technical expertise. By addressing important limitations of AM, blockchain is expected to improve the competitiveness of AM in parts’ production, catalyzing the trend toward more decentralized manufacturing resulting in more agile, resilient, and flexible supply chains and reduced logistics costs. Beyond that, blockchain‐based AM platforms are expected to enhance supply chain visibility, drive supply chain digitalization, support supply chain finance, and contribute to the emergence of shared factory systems.  相似文献   
2.
Traffic congestion is an unpreventable problem to avoid in a transportation network and it has negative effects on traffic accident, time wasting, traffic delay and safety problem. Besides, in transportation networks, drivers do not want to deal with traffic jam while traversing between specified origin-destination pair. Therefore, traffic assignment (TA) is imperative to improve traffic management, transportation safety, time, and cost savings. System Optimum Traffic Assignment Problem (SOTAP) is a kind of TA model which aims to minimize the total system travel time on the network, and satisfies the flow conservation constraints. To model the SOTAP more realistically, the imprecise parameters can be taken as fuzzy. Therefore, in this paper, we focus on converting the conventional SOTAP to a fuzzy quadratic programming problem (QPP) which is named System Optimum Fuzzy Traffic Assignment Problem (SOFTAP). Here, link travel time is expressed with BPR function as generally used in the literature by converting to fuzzy except link-dependent parameters. Thus, the nonlinear objective function of SOFTAP is expressed in terms of fuzzy link flows and fuzzy link travel times. A solution approach from the literature is modified to the reconstructed SOFTAP.  相似文献   
3.
尚梅 《基建优化》2003,24(6):7-8,11
建筑工程资格预审无论对业主还是对承包商都至关重要,根据建筑工程的特点,在目前普遍采用的资格预审评价方法的基础之上,总结了进行资格预审的评价指标体系,并提出了基于模糊数学意见集中排序法的建筑工程资格预审方法。  相似文献   
4.
周敏  李建华 《改革与战略》2008,24(10):191-193
知识管理是现代企业管理的重要内容。正确分析和评价企业的知识管理绩效,对于促进企业知识管理、提高企业知识管理水平以及增强企业竞争优势,具有重要的现实意义。文章构建了企业知识管理绩效评价的指标体系,并运用模糊综合评价模型对企业知识管理绩效进行了综合评价。  相似文献   
5.
It is still disputed whether foresight exercises should be based on top-expert assessments or on a broader base of less specialised experts, and whether the self-rating of experts is an acceptable method. Using the German 1993 and the Austrian 1998 Technology Delphis, this study addresses both questions. Self-rating is, in fact, an appropriate method for selecting experts. But the assessment of self-rated top experts tend to suffer from an optimism bias due to the experts' involvement and their underestimation of realisation and diffusion problems. The degree of optimism is positively correlated with the degree of self-rated knowledge, and it is more pronounced for the least pioneering and for organizational innovations. Experts with top self-ratings working in business have a stronger optimism bias than those working in the academia or in the administration: Consistent with the insider hypothesis, they are most optimistic with regard to realisation, innovativeness, and potential leadership in economic exploitation. Given the optimism bias, foresight exercises should base their panels on a fair mixture of experts of different grades, with different types of knowledge and affiliation, and not only on top specialists of the respective field. Delphi-type exercises, therefore, offer an advantage relative to forum groups or small panels of specialists.  相似文献   
6.
设计了一个烧结模糊控制系统,进而构建了一个基于模糊控制的自适应脉宽控制器,对煤气阀、换向阀开关时间进行控制;利用模糊控制器的模糊推理能力来实现煤气阀门开度在线调整,以达到优化控制的目的。运行结果表明,这种控制器与常规比值控制器相比可以取得较好的控制效果。  相似文献   
7.
Yoshiharu Takamura 《Socio》2003,37(2):85-102
As a national project of Japan, plans for the relocation of several government agencies out of Tokyo have been ongoing. This paper is concerned with the problem of site selection for this project. The National Land Agency, the agency responsible for this project, has declared that the process of site selection should be rational, open to the public and easily understandable. In an effort to meet these requirements, we propose a consensus-making method for reaching a group decision, based on a combination of the analytic hierarchy process (AHP) and the Assurance Region model of data envelopment analysis (DEA). Several strategic uses of these methodologies, e.g., Delphi procedures, are also discussed. Based on these analyses, the “Wise Men” Committee for deciding the best site has chosen two from among ten contenders, one from the North-East and the other from the Central part of Japan, as candidates for the best relocation site. We could not discriminate between the two with respect to the multiple criteria chosen for evaluating sites. The Committee recommended the two sites to the Prime Minister at the end of December 1999. The Prime Minister reported this conclusion to the Diet. This topic is currently the focus of political discussions in the Diet. In this report, the authors summarize the decision-making processes that the Wise Men Committee followed, putting emphasis on the methodological aspects.  相似文献   
8.
This article classified gas exploration risk on the basis of the characteristics of oil-gas exploration investment projects, which are internal systems risk and external non-systemic risk. It described each classification specifically and introduced the basic principles and mathematical model of the multi-factor hierarchical fuzzy comprehensive judgment in detail, and then researched the conducts the risk of the gas exploration with examples.  相似文献   
9.
徐刚 《物流技术》2007,26(7):121-122,133
应用层次分析方法的思想,从航材保障对第三方物流的要求制定了科学的评价指标体系。结合指标体系利用模糊评价方法,构建了对第三方物流企业的选择模型,对航材保障中的第三方物流企业做出基本的评价,提供了科学的选择方案。  相似文献   
10.
Probability theory in fuzzy sample spaces   总被引:2,自引:0,他引:2  
This paper tries to develop a neat and comprehensive probability theory for sample spaces where the events are fuzzy subsets of The investigations are focussed on the discussion how to equip those sample spaces with suitable -algebras and metrics. In the end we can point out a unified concept of random elements in the sample spaces under consideration which is linked with compatible metrics to express random errors. The result is supported by presenting a strong law of large numbers, a central limit theorem and a Glivenko-Cantelli theorem for these kinds of random elements, formulated simultaneously w.r.t. the selected metrics. As a by-product the line of reasoning, which is followed within the paper, enables us to generalize as well as to bring together already known results and concepts from literature.Acknowledgement. The author would like to thank the participants of the 23rd Linz Seminar on Fuzzy Set Theory for the intensive discussion of the paper. Especially he is indebted to Professors Diamond and Höhle whose remarks have helped to get deeper insights into the subject. Additionally, the author is grateful to one anonymous referee for careful reading and valuable proposals which have led to an improvement of the first draft.This paper was presented at the 23rd Linz Seminar on Fuzzy Set Theory, Linz, Austria, February 5–9, 2002.  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