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   8403篇
  免费   294篇
  国内免费   120篇
财政金融   595篇
工业经济   352篇
计划管理   2047篇
经济学   1504篇
综合类   1372篇
运输经济   56篇
旅游经济   78篇
贸易经济   931篇
农业经济   985篇
经济概况   896篇
信息产业经济   1篇
  2024年   21篇
  2023年   93篇
  2022年   120篇
  2021年   172篇
  2020年   230篇
  2019年   132篇
  2018年   107篇
  2017年   152篇
  2016年   172篇
  2015年   212篇
  2014年   538篇
  2013年   556篇
  2012年   703篇
  2011年   893篇
  2010年   703篇
  2009年   560篇
  2008年   651篇
  2007年   661篇
  2006年   554篇
  2005年   378篇
  2004年   280篇
  2003年   240篇
  2002年   172篇
  2001年   142篇
  2000年   109篇
  1999年   56篇
  1998年   42篇
  1997年   30篇
  1996年   33篇
  1995年   12篇
  1994年   16篇
  1993年   14篇
  1992年   15篇
  1991年   16篇
  1990年   2篇
  1989年   5篇
  1988年   6篇
  1987年   5篇
  1986年   5篇
  1985年   1篇
  1984年   3篇
  1983年   3篇
  1981年   2篇
排序方式: 共有8817条查询结果,搜索用时 15 毫秒
1.
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   
2.
Systems’ thinking places high value on understanding the context. This study focused on the collection of disaggregated data in order to understand the context, to facilitate improvement of health outcomes. The aim of this article was to assess the implementation of municipal ward-based health data collection (disaggregated data) and health care workers’ perceptions of this data collection process. This cross-sectional study used mixed methods in Amajuba district. The participants were professional nurses at the Primary Health Care level. Of the 131 respondents, 123 (93.9%) collected municipal ward-based health data, and found it useful. Opportunities for improving data collection were identified. Disaggregation of the data at ward level contributes to a better understanding of the target population’s health, assists planning for health needs and enables provision of targeted interventions in order to improve health outcomes, to prevent financial regression and waste of health resources.  相似文献   
3.
This paper discusses the specifics of forecasting using factor-augmented predictive regressions under general loss functions. In line with the literature, we employ principal component analysis to extract factors from the set of predictors. In addition, we also extract information on the volatility of the series to be predicted, since the volatility is forecast-relevant under non-quadratic loss functions. We ensure asymptotic unbiasedness of the forecasts under the relevant loss by estimating the predictive regression through the minimization of the in-sample average loss. Finally, we select the most promising predictors for the series to be forecast by employing an information criterion that is tailored to the relevant loss. Using a large monthly data set for the US economy, we assess the proposed adjustments in a pseudo out-of-sample forecasting exercise for various variables. As expected, the use of estimation under the relevant loss is found to be effective. Using an additional volatility proxy as the predictor and conducting model selection that is tailored to the relevant loss function enhances the forecast performance significantly.  相似文献   
4.
从考察企业组织的敏捷性与交易成本的相互关系入手,对企业组织敏捷性的影响因素进行了剖析。详细分析了信息技术(IT)对提高企业组织敏捷性的作用机理。指出IT正是通过降低企业内、外部的交易成本、缩短流程时间、提高人的认识理性、扼制机会主义、促进企业组织结构、决策方式  相似文献   
5.
The objective of this paper is to determine the best predictor of equity market crashes by focusing particularly on volatility and market liquidity. In finance, volatility has traditionally been regarded as the best measure of market risk. However, this paper shows that the forecast value of market liquidity, in particular our modified calculated market depth, predicts equity market crashes much more accurately than does the forecast values of EGARCH or Implied Volatility.  相似文献   
6.
This paper demonstrates howadditional rents are generated in a fisherycharacterized by intraseasonal variation infish characteristics, including size,condition, and composition. Based on anexpanded conceptual model of the optimalharvest rule, fish characteristics affect preand post harvest production yields and outputprices. A dynamic empirical model, which uses asystem of quality characteristics and anhedonic equation, illustrates the complexrelationships and management choices associatedwith internalizing seafood qualitycharacteristics in a hake fishery. The modelretains the regulated open access managementsystem, but controls intertemporal andintersectoral quotas, production portfolios,and total allowable catch. Results demonstratethat including revenue-side effects frominternalizing fish quality can generatesignificantly greater rents and reduce therelative benefits of increased productionyields. If excluded, bioeconomic models canunderestimate the level of regulatory rentdissipation and overemphasize managementobjectives such as full utilization, whichcould misdirect processing decisions and resultin a suboptimal resource management plan.Implications for data collection,multidisciplinary analysis, and improvements inmarine resource management are discussed.  相似文献   
7.
伴随中国私营经济而发生的私营资本原始积累,对中国的经济社会发展,对加速中国的社会主义现代化建设,是功绩卓著的。中国之所以能在20世纪末达到小康,私营资本原始积累是立下汗马功劳的。在中国今后的全面小康社会建设中私营资本原始积累必将发挥越来越大的功效。  相似文献   
8.
从功能出发进行对外汉语语法教学的研究与实践   总被引:1,自引:0,他引:1  
该文系统地总结了作者进行对外汉语语法教学的实践经验——从功能出发进行对外汉语语法教学,具体从三个方面入手:一、语法教学和词汇教学相结合;二、句法结构和语义结构相结合;三、语法知识和语言环境相结合。  相似文献   
9.
目前,中国建设银行已建立了总行垂直管理的内部审计体制,内部审计的地位得到了进一步的巩固和加强,管理层对内部审计也提出了更高的要求。本文就如何发挥审计的建设性职能,最大程度地做好审计增值服务,促进银行价值和运作效率的提升,实现审计职能从查错防弊向防护决策和建设性方面转变做初步探讨。  相似文献   
10.
新形势下我国耕地保护的长效机制研究   总被引:1,自引:0,他引:1  
耕地是人类赖以生存的物质基础,是国民经济和社会发展的宝贵资源,耕地数量的多少和质量优劣直接关系到国家粮食安全和社会稳定。因此,在新形势下,如何保护好有限的耕地资源,促进经济社会科学、合理地发展,已成为当今世界的重大课题。本文根据我国耕地减少的现实危机及原因,提出一套科学、合理的耕地保护长效机制,力求为进一步有效地保护耕地资源提供理论基础和现实途径。  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