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   6106篇
  免费   170篇
  国内免费   85篇
财政金融   485篇
工业经济   499篇
计划管理   2329篇
经济学   678篇
综合类   549篇
运输经济   69篇
旅游经济   106篇
贸易经济   806篇
农业经济   332篇
经济概况   508篇
  2024年   10篇
  2023年   56篇
  2022年   101篇
  2021年   165篇
  2020年   173篇
  2019年   131篇
  2018年   114篇
  2017年   141篇
  2016年   131篇
  2015年   210篇
  2014年   484篇
  2013年   587篇
  2012年   476篇
  2011年   635篇
  2010年   476篇
  2009年   362篇
  2008年   422篇
  2007年   359篇
  2006年   326篇
  2005年   249篇
  2004年   174篇
  2003年   143篇
  2002年   102篇
  2001年   66篇
  2000年   63篇
  1999年   45篇
  1998年   25篇
  1997年   30篇
  1996年   25篇
  1995年   18篇
  1994年   12篇
  1993年   8篇
  1992年   10篇
  1991年   9篇
  1990年   2篇
  1989年   4篇
  1988年   2篇
  1986年   3篇
  1985年   5篇
  1984年   3篇
  1983年   2篇
  1980年   1篇
  1978年   1篇
排序方式: 共有6361条查询结果,搜索用时 15 毫秒
161.
This tutorial provides an introduction to Palm distributions for spatial point processes. Initially, in the context of finite point processes, we give an explicit definition of Palm distributions in terms of their density functions. Then we review Palm distributions in the general case. Finally, we discuss some examples of Palm distributions for specific models and some applications.  相似文献   
162.
In this study, ten bioenergy crop rotations (corn, corn-stover, sorghum, soybean, corn-soybean, corn-soybean-canola, corn-stover-soybean, miscanthus, switchgrass, and sorghum-soybean) were selected based on local stakeholder (economically motivated) and regulator (environmentally motivated) preferences. These crops were implemented on diverse landscapes (agricultural, marginal, and agricultural plus marginal lands) one at time for 17 years using a SWAT model of the Saginaw River Watershed in Michigan. The bioenergy crops were evaluated based on 100 percent, 50 percent, and zero percent weight assigned to both stakeholders’ and regulators’ preferences using analytic hierarchy process (AHP), an optimization and decision-making technique that aims to satisfy multiple conflicting objectives. The corn-soybean-canola rotation was selected in all landscapes based on economic benefits (stakeholders’ preferences). Meanwhile, perennial grasses (miscanthus and switchgrass) were selected based on environmental benefits (regulators’ preferences), because they maintain permanent cover, require fewer inputs than traditional row crops, and are less management intensive. When implementing bioenergy crops on marginal lands, pollution generation greatly increased at the field level, indicating that these lands are likely not viable for bioenergy crop production to meet potential future renewable energy demand.  相似文献   
163.
164.
The endogenous grid method (EGM) significantly speeds up the solution of stochastic dynamic programming problems by simplifying or completely eliminating root-finding. We propose a general and parsimonious EGM extended to handle (1) multiple continuous states and choices, (2) multiple occasionally binding constraints, and (3) non-convexities such as discrete choices. Our method enjoys the speed gains of the original one-dimensional EGM, while avoiding expensive interpolation on multi-dimensional irregular endogenous grids. We explicitly define a broad class of models for which our solution method is applicable, and illustrate its speed and accuracy using a consumption–saving model with both liquid assets and illiquid pension assets and a discrete retirement choice.  相似文献   
165.
Internationalization of company activities is the necessity of the development for majority of entrepreneurial subjects in the Czech Republic. Internationalization of entrepreneurial activities becomes a tool of business competitiveness. Selecting the right foreign entry mode is an important decision, which demands a lot of resources and thorough planning. The factors influencing company's choice of entry mode are divided into two main groups subsuming--external and internal factors. External factors consist of determinants regarding the company's environment while the intemal ones are determined by the company's specific factors. The opening of new markets such as in the Czech Republic has created the potential for small and medium-size enterprise (SME) expansion and investment. The objective of this paper is to present an application of the entry modes of the selected Czech entrepreneurial subjects. The companies included in the study are those that have undertaken internationalization activities and are incorporated in the Czech Republic. There were a total of 297 enterprises that participated in the research. The research method was an oral questioning and the main instrument was a questionnaire. A relatively low degree of Czech companies that have undergone intemationalization has resulted in the dominance of the least advanced forms of internationalization expansion, mainly exports with a small share of more advanced forms of foreign direct investments and a very low level of forms of international cooperation. Czech companies are in decision about the choosing the foreign entry mode influenced by the many factors. The greatest influence on the choice of foreign entry mode has entry mode variables. Entry mode variables constitute variables assessment characteristics of particular entry mode.  相似文献   
166.
黄红梅 《价值工程》2014,(32):242-243
本文通过全面剖析影响交通冲突的原因,以交通流量、道路几何设计和道路环境三方面的因素建立指标层次结构体系。提出基于模糊层次分析(FAHP)法优化BP神经网络(BPNN)的预测模型,应用于交通冲突预测。  相似文献   
167.
Workload control under continuous order release   总被引:1,自引:0,他引:1  
Workload control is a production planning and control concept specifically designed for complex manufacturing environments. Past research on Workload control has been essentially focused on discrete order release. This means that release of orders to the shop floor takes places on a periodic basis. Continuous order release has been somehow neglected, in spite of its apparent potential for improving system performance, including the reduction of order flow times. This paper presents a simulation study of this order release approach. The study contributes for improving the basis for setting workload norms, selecting the workload control strategy and deciding upon routing alternatives under continuous order release.  相似文献   
168.
This paper investigates the link between a firm's process innovation (PI) and its segment productivity at different life cycles. The results show that business diversification is negatively associated with a firm's productivity, and further reveal that a firm's PI moderates the above relationship. In addition, the corporate life cycle literature builds blocks for this study to explain that the involvement of administrative costs varies across life cycles when diversified firms get mature and bigger. Our empirical evidence indicates that the potential costs of a complex organisational structure contingent on business diversification at a firm's mature life cycle could be alleviated by the conduct of process innovation. As process innovation at different life cycles may alter managerial incentive that leads to different firm performance, the managerial implication is that diversified firms should appropriately engage in process innovation to prevent unfavourable liability from the development of their businesses.  相似文献   
169.
We develop a dynamic factor model to forecast the implied volatility surface (IVS) of Shanghai Stock Exchange 50ETF options. Based on the assumption that dynamic change in IVS is mean-reverting and Markovian, we use a state space model to capture the dynamics of IVS, and set the latent factors to be the Ornstein–Uhlenbeck processes. We obtain the optimal estimations of parameters using the Kalman filter algorithm. Empirical results show that our model performs better than the traditional IVS model in terms of fitting ability and prediction performance.  相似文献   
170.
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