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   3719篇
  免费   67篇
财政金融   350篇
工业经济   863篇
计划管理   647篇
经济学   945篇
综合类   107篇
运输经济   17篇
旅游经济   109篇
贸易经济   352篇
农业经济   89篇
经济概况   300篇
信息产业经济   2篇
邮电经济   5篇
  2024年   6篇
  2023年   33篇
  2022年   35篇
  2021年   52篇
  2020年   74篇
  2019年   69篇
  2018年   66篇
  2017年   94篇
  2016年   85篇
  2015年   59篇
  2014年   87篇
  2013年   207篇
  2012年   196篇
  2011年   523篇
  2010年   441篇
  2009年   342篇
  2008年   270篇
  2007年   262篇
  2006年   257篇
  2005年   230篇
  2004年   98篇
  2003年   71篇
  2002年   86篇
  2001年   29篇
  2000年   31篇
  1999年   14篇
  1998年   22篇
  1997年   4篇
  1996年   7篇
  1995年   8篇
  1994年   2篇
  1993年   7篇
  1992年   1篇
  1991年   4篇
  1990年   3篇
  1986年   2篇
  1985年   3篇
  1984年   1篇
  1983年   1篇
  1981年   1篇
  1979年   1篇
  1945年   2篇
排序方式: 共有3786条查询结果,搜索用时 15 毫秒
1.
Product life cycle (PLC) prediction plays a crucial role in strategic planning and policy definition for high-technology products. Forecast methodologies which can predict PLCs accurately can help to achieve successful strategic decision-making, forecasting, and foresight activities in high-technology firms, research institutes, governments, and universities. Over the past few decades, even though analytic framework strategies have been proposed for production, marketing, R&D (research and development), and finance, aiming at each stage of PLCs, forecast methodologies with which to predict PLCs are few. The purpose of this research is to develop a novel forecast methodology to allow for predictions of product life time (PLT) and the annual shipment of products during the entire PLC of multiple generation products. A novel two-stage fuzzy piecewise regression analysis method is proposed in this paper. In the first stage, the product life-time of the specific generation to be analyzed will be predicted by the fuzzy piecewise regression line that is derived based upon the product life-time of earlier generations. In the second stage of the forecast methodology, the annual shipment of products of the specified generation will be predicted by deriving annual fuzzy regression lines for each generation, based upon the historical data on the earlier generations' products. An empirical study predicting the life-time and the annual shipment of the 16 Mb (Mega bit) DRAM (Dynamic Random Access Memory) PLC is illustrated to validate the analytical process. The results demonstrate that two-stage fuzzy piecewise regression analysis can predict multiple generation PLT and PLC precisely, thereby serving as a foundation for future strategic planning, policy definitions and foresights.  相似文献   
2.
A wide range of intractable problems such as polluting emissions, noise, accidents, resource depletion, and inaccessibility of amenities are associated with the current transport regime. Given the slow movement towards a more sustainable mobility system, more radical, systemic innovation - a ‘transition’ - is required. Broadly speaking, this may be achieved via three routes: technological change, modal shift, and reduced travel demand. Drawing on concepts from the transitions literature (e.g., [Geels, F.W.: Technological Transitions and System Innovations: A Co-evolutionary and Socio-Technical Analysis, Edward Elgar, Cheltenham, 2005.]), we conceptualise each of these routes as a bundle of niche activities within an Area of Innovation, deviating to differing degrees from the current mobility ‘regime’. We present empirical evidence and indications of ongoing development of niches in these three areas within the UK and Sweden, and explore processes of co-evolution, divergence and tension within and between niches. Findings indicate recent market penetration of novel transport technologies, more advanced than modal shift or demand management activities; however, different transport technologies are more successful in each country. We also identify examples of a close relationship between development of radical vehicle/fuel technologies and provision of mobility services; and information technology as a driver in all three areas of innovation. We conclude that future innovation in transport depends on diversity, hybridisation, and co-evolution of niches. Finally, policy implications are discussed.  相似文献   
3.
Many see Nanotechnology as the technology that will underlie the next Schumpeterian wave creating new opportunities for wealth and job creation. Further it is a process based or materials technology. Yet all currently used models of innovation are based on assembled products or service products and these simply do not recognize the differences in materials products nor the “enabling” nature of Nanotechnologies. If nanotechnology is poised to become the economic engine of this millennium and if current models of innovation, which are utilized, by policy makers and firm based strategist alike are based on technology product paradigms that are dissimilar to the realities of nanotechnology and other process-based technologies then there is cause for concern.Here the authors provide a model and supporting cases demonstrating a new process or materials based innovation model that is based on the tight coupling between product and process innovation of not only Nanotechnology-based products but other process-based products. This is an important finding, because it identifies and remedies a gap in the literature associated with earlier process and product innovation models. For process-based products like materials, food, chemicals and nanotechnologies any change to the manufacturing processes results in significant changes in end product features. The implications of this model to practice are considered.  相似文献   
4.
I analyze the value of a nonstandard call option that allows the holder to purchase an underlying asset at a discount proportional to the asset's market price. Several applications for this type of option exist, including its use in employee compensation contracts. I derive the value of this option for a dividend-paying asset and for an option whose exercise price reflects a time-varying discount factor. The derived value incorporates the optimal time at which the option should be exercised. One application of this option relates to a residential real estate program in China.  相似文献   
5.
板峪口—上寨地区位于太行山中段阜平穹褶束与五台山—恒山花岗绿岩带汇合部位。该区发育两期韧性剪切带,第一期为拆离—滑脱型韧性剪切带;第二期为逆冲推覆型韧性剪切带。本文重点总结了韧性剪切带地质特征,并对其地质意义进行了讨论。认为原五台群为由一系列韧性剪切带分割的构造岩片叠置体。板峪口组和五台群金刚库组中的部分中深变质片麻岩为“外来岩片。”原五台山群与阜平群为由韧性剪切带接触。并总结了韧性剪切带对金矿的成矿、控矿规律。  相似文献   
6.
水质分析中测定总氮影响因素的探讨   总被引:1,自引:0,他引:1  
针对总氮测定时遇到试验空白值偏高的情况,分析了实验环境、实验用水、试剂、玻璃器皿、消解过程以及所用设备等方面对空白值的影响,并提出减少空白值的对策。  相似文献   
7.
汇率变动、市场份额与中国纺织品服装出口竞争力   总被引:4,自引:1,他引:3  
谷任  吴海斌 《世界经济》2007,40(3):41-48
本文选取中国纺织品服装出口的主要海外市场——美国作为研究范围,将韩国、印度和巴基斯坦分别作为中国棉纱、棉机织物和服装成衣类纺织品出口的主要竞争对手,探讨在人民币实际有效汇率波动和贸易争端引起的市场份额不稳定的情况下,以上三类产品国际竞争力的不同表现及人民币实际有效汇率波动对中国以上三类产品价格的传递系数。研究结果显示:汇率变动对服装类和棉纱类出口价格影响具有完全传递性。导致汇率波动的压力直接传递到出口产品价格上;中国相对较高的市场份额对产品价格的积极影响力并不太大,而贸易争端导致的市场份额不稳定对以上三类纺织品的国际竞争力造成了不同程度的影响。  相似文献   
8.
随着信息技术与会计领域结合的日益紧密,对现代会计发展的安全问题提出了严峻的挑战和一些新的要求。  相似文献   
9.
跨国公司研究与开发的国际化是21世纪初跨国公司发展的新态热,近几年,跨国公司在华设立的研发机构不断增加,这种国际技术转移的新形式既是跨国公司实施其全球化战略的需要,也将对东道国-中国的经济发展产生深远的影响。  相似文献   
10.
论珠江上游地区旅游商品文化的提炼   总被引:2,自引:0,他引:2  
珠江上游地区旅游商品文化的提炼有着一些有利条件,也存在着一些不利因素。珠江上游地区旅游商品文化的提炼的基本思路是以旅游商品的开发为载体,以地方文化背景为依托,加强旅游商品的设计和包装,实现传统工艺和现代技术手段的有机结合。  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