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   8496篇
  免费   259篇
财政金融   1773篇
工业经济   726篇
计划管理   1378篇
经济学   1791篇
综合类   112篇
运输经济   96篇
旅游经济   165篇
贸易经济   1780篇
农业经济   260篇
经济概况   602篇
信息产业经济   4篇
邮电经济   68篇
  2023年   57篇
  2022年   49篇
  2021年   83篇
  2020年   121篇
  2019年   200篇
  2018年   222篇
  2017年   252篇
  2016年   216篇
  2015年   181篇
  2014年   278篇
  2013年   978篇
  2012年   320篇
  2011年   363篇
  2010年   332篇
  2009年   372篇
  2008年   329篇
  2007年   282篇
  2006年   264篇
  2005年   287篇
  2004年   241篇
  2003年   247篇
  2002年   242篇
  2001年   196篇
  2000年   182篇
  1999年   185篇
  1998年   146篇
  1997年   159篇
  1996年   130篇
  1995年   120篇
  1994年   128篇
  1993年   115篇
  1992年   111篇
  1991年   96篇
  1990年   69篇
  1989年   74篇
  1988年   68篇
  1987年   68篇
  1986年   69篇
  1985年   116篇
  1984年   93篇
  1983年   83篇
  1982年   90篇
  1981年   67篇
  1980年   74篇
  1979年   71篇
  1978年   59篇
  1977年   61篇
  1976年   59篇
  1974年   33篇
  1973年   22篇
排序方式: 共有8755条查询结果,搜索用时 8 毫秒
71.
Management Review Quarterly - Additive manufacturing (AM) is regarded as a technology that has transformative and disruptive potential in nearly all industries. However, AM is not only about new...  相似文献   
72.
Conservation is a crisis discipline requiring rapid action with limited funds. This study examines the potential of socioeconomic variables to predict forest use values. If natural resource use can be predicted from socioeconomic data, conservation planners could rapidly identify and focus conservation programs on the sectors of local populations that most intensively utilize local flora and fauna. Families in three communities in the northern Peruvian Amazon were surveyed over a 6-month period. Data were collected on use of flora and fauna from six locally determined use categories (food, medicine and poisons, wood, weavings, adornments, and “other”) in forest types of three age classes (fallow fields—very young forests, young secondary forests, and old secondary forests). Forest use values were the dependant variables calculated in $/ha/year. Socioeconomic variables included: age, education, family size, residence time, land worked, land owned, number of fishing nets, chickens, pigs, cows, and/or mules owned (all proxies for productive assets), and level of ecological knowledge (ability of informants to correctly identify forest species and answer basic questions about their biology). Ordinary least square multiple regressions were run independently for each forest type. Regressions were also run separately for the two most valuable use categories, food and wood. Low R2 adjusted values (all < 0.3) reflect the difficulty in predicting human behavior due to confounding variables and complex interactions. Residence time and a household's community of residence were the most significant predictors of forest use values. Households in Vista Alegre, the community with the highest density of people and smallest landholdings per household, extracted the highest value of forest products per hectare. The longer a family stayed in any community the higher the value of forest goods they extracted. If families that lived in an area longest are the most intensive extractors of forest products, they should be a major focus for conservation programming. In addition, the higher value of products extracted from forests by some families may make them more open to strategies seeking to protect long-term viability of the resources they utilize. The importance of residence time also indicates that planners need to account for changes in the resource use patterns of stakeholders over time.  相似文献   
73.
74.
75.
The Kyoto Protocol foresees emission trading but does not yet specify verification of (uncertain) emissions. This paper analyses a setting in which parties can meet their emission targets by reducing emissions, by investing in monitoring (reducing uncertainty of emissions) or by (bilaterally) trading permits. We derive the optimality conditions and carry out various numerical simulations. Our applications suggest that including uncertainty could increase compliance costs for the USA, Japan and the European Union. Central Europe and the Former Soviet Union might be able to gain from trading due to higher permit prices. Emissions trading could also lower aggregate uncertainty on emissions.  相似文献   
76.
77.
Summary. We analyze an oligopoly model of homogeneous product price competition that allows for discontinuities in demand and/or costs. Conditions under which only zero profit equilibrium outcomes obtain in such settings are provided. We then illustrate through a series of examples that the conditions provided are “tight” in the sense that their relaxation leads to positive profit outcomes. Received: April 7, 2000; revised version: September 14, 2000  相似文献   
78.
Gasoline divorcement regulations restrict the integration of gasoline refiners and retailers. Theoretically, vertical integration can harm competition, making it possible that divorcement policies could increase welfare; alternatively, these policies may reduce welfare by sacrificing efficiencies. This paper attempts to differentiate between these possibilities by estimating a reduced form equation for the real retail price of unleaded regular gasoline. I find that divorcement regulations raise the price of gasoline by about 2.6¢ per gallon, reducing consumers surplus by over $100 million annually. This finding suggests that current proposals to further separate gasoline retailing from refining will be harmful to gasoline consumers.  相似文献   
79.
Competition was introduced into the electric utility industry with the passage of the Public Utilities Regulatory Policy Act (PURPA) of 1978. Increasing interest has appeared in structuring the PURPA purchase market into an auction system. This paper addresses the design issues associated with setting up such markets and introduces a simulation model to study them. The simulation analysis is guided by theoretical issues such as the alleged inefficiency of first-price auctions. We find that efficiency concerns raised about first-price auctions turn out to be less important than simple theoretical concerns would suggest.  相似文献   
80.
Levels of insurance against unemployment vary considerably across countries. Replacement rates, the ratio relating income from unemployment to what people earned when they were employed, are higher in countries with proportional electoral systems than in countries with majoritarian systems. Also, replacement rates are positively correlated with per capita income and negatively correlated with the countries' unemployment rates. I develop an electoral competition model that replicates these stylized facts.  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