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   1942篇
  免费   92篇
  国内免费   16篇
财政金融   78篇
工业经济   406篇
计划管理   511篇
经济学   371篇
综合类   99篇
运输经济   52篇
旅游经济   39篇
贸易经济   115篇
农业经济   167篇
经济概况   212篇
  2024年   18篇
  2023年   41篇
  2022年   61篇
  2021年   78篇
  2020年   70篇
  2019年   53篇
  2018年   37篇
  2017年   83篇
  2016年   59篇
  2015年   108篇
  2014年   205篇
  2013年   195篇
  2012年   206篇
  2011年   201篇
  2010年   135篇
  2009年   83篇
  2008年   74篇
  2007年   61篇
  2006年   55篇
  2005年   61篇
  2004年   36篇
  2003年   31篇
  2002年   23篇
  2001年   9篇
  2000年   18篇
  1999年   14篇
  1998年   8篇
  1997年   6篇
  1996年   8篇
  1995年   3篇
  1994年   5篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
排序方式: 共有2050条查询结果,搜索用时 31 毫秒
11.
鸡西盆地是一个多煤层、多煤种的中、新生代聚煤盆地,丰富的煤炭资源为煤成气的形成提供了充足的物质基础。不但生产矿井具有明显的矿井瓦斯显示,而且在以往的地质勘探过程中曾发现过喷气钻孔,经研究这是煤成气的直接显示。本文主要应用煤岩学的基本理论和方法,通过分析各种煤岩组分的生烃能力以及鸡西盆地的显微组分分析,并结合其它方面的研究,来阐述鸡西盆地的煤成气前景。  相似文献   
12.
油气生产经营的市场竞争日趋激烈 ,如何以较低的经营成本为市场提供所需的油气能源 ,是石油企业降低生产经营风险、提高经济效益的利器。本文通过充分调查分析石油企业油气勘探、开发、开采成本的历史数据资料 ,研究油气成本项目的构成、特征、趋势及影响原油生产成本的因素 ,提出降低成本的主要措施 ,有利于石油企业实现全面的成本控制  相似文献   
13.
基于2013-2020年的30个省份数据构建面板数据模型,从碳排放总量和碳排放强度两个视角研究数字经济发展对区域碳排放的影响。研究发现:数字经济的发展有效地降低了人均碳排放量、碳排放增量与碳排放增速,数字经济与碳排放强度之间存在倒“U”形关系,数字经济与碳排放强度、边际碳排放强度的关系呈现区域性特征,在省域层面数字经济对边际碳排放强度的影响不存在明显的空间效应,数字经济对碳排放增长率的影响存在基于产业结构优化、人口集聚、城镇化的遮掩效应。  相似文献   
14.
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   
15.
Environmental Product Differentiation and Environmental Awareness   总被引:1,自引:0,他引:1  
In this paper, we have considered a duopolistic model of environmental product differentiation with two types of consumers (green and brown) to analyze how environmental awareness affects the environment. “Green” consumers value the physical and environmental attributes of the good they purchase while “brown” consumers only value the physical attributes. We find that more environmental awareness may not be good news for the environment as the firm that produces the good without environmental attributes may increase its sales. The result depends on the degree of product differentiation and the cost to achieve it. Social welfare can also be inversely related to environmental awareness if the negative environmental effect dominates the positive market effect.   相似文献   
16.
We propose enforcement strategies for emissions trading programs with bankable emissions permits that guarantee complete compliance with minimal enforcement costs. Our strategies emphasize imperfect monitoring supported by a high unit penalty for reporting violations, and tying this penalty directly to equilibrium permit prices. This approach is quite different from several existing enforcement strategies that emphasize high unit penalties for emissions in excess of permit holdings. Our analysis suggests that a high penalty for excess emissions cannot be used to conserve monitoring effort, and that it may actually increase the amount of monitoring necessary to maintain compliance.The authors are grateful to Anthony Heyes and three anonymous referees for their valuable comments. Partial support for this research was provided by the Cooperative State Research Extension, Education Service, U. S. Department of Agriculture, Massachusetts Agricultural Experiment Station under Project No. MAS00871.  相似文献   
17.
Use of biofuels diminishes fossil fuelcombustion thereby also reducing net greenhousegas emissions. However, subsidies are neededto make agricultural biofuel productioneconomically feasible. To explore the economicpotential of biofuels in a greenhouse gasmitigation market, we incorporate data onproduction and biofuel processing for thedesignated energy crops switchgrass, hybridpoplar, and willow in an U.S. AgriculturalSector Model along with data on traditionalcrop-livestock production and processing, andafforestation of cropland. Net emissioncoefficients on all included agriculturalpractices are estimated through crop growthsimulation models or taken from the literature. Potential emission mitigation policies ormarkets are simulated via hypothetical carbonprices. At each carbon price level, theAgricultural Sector Model computes the newmarket equilibrium, revealing agriculturalcommodity prices, regionally specificproduction, input use, and welfare levels,environmental impacts, and adoption ofalternative management practices such asbiofuel production. Results indicate no rolefor biofuels below carbon prices of $40 perton of carbon equivalent. At these incentivelevels, emission reductions via reduced soiltillage and afforestation are more costefficient. For carbon prices above $70,biofuels dominate all other agriculturalmitigation strategies.  相似文献   
18.
Emission of CO2, SO2 and NOx are all closely linked to the burning of fossil fuels. Here we report on simulations done by linking a Sectoral European Energy Model (SEEM), covering energy demand in nine Western European countries, with the emission-transport-deposition model RAINS developed by IIASA. The study analyses emissions of CO2, SO2 and NOx, deposition of sulphur and nitrogen and the extent of areas where the critical load for sulphur is exceeded in year 2000 under four different energy scenarios. Two different sets of future behavioural patterns for the thermal electric power production sector are considered. In one regime, called the plan-efficient regime, the sector is assumed to follow official plans with regard to investment in new capacity. In the other regime, called the cost-efficient regime, the thermal power sector is assumed to behave in a cost minimizing manner. The effects of the proposed EC carbon/energy tax are studied under both regimes, giving rise to altogether four scenarios.In both regimes the effect of the EC tax is to reduce emissions by between 6 and 10 per cent in year 2000 relative to the scenarios without the tax. A change of regime, from the regulated, plan-efficient regime to the market-based, cost-efficient regime, will, by itself, reduce emissions of CO2 and NOx by approximately 3 per cent, while SO2 emissions are reduced by 13 per cent. The EC tax will reduce sulphur deposition by more than 5 per cent in the nine model countries under the plan-efficient regime. A change of regime further reduces the total deposition by 9 per cent. The area where depositions exceed the critical load is reduced by approximately 6 per cent in year 2000 by the tax in both regimes. Changing from the plan-efficient to the cost-efficient regime has a similar impact.Although the emission reductions due to the EC tax may seem modest, they are shown to have a sizeable effect on the technological abatement costs of reaching targets like those prescribed in the Sofia protocol on the stabilisation of NOx emissions, and the Helsinki protocol on SO2 emission reductions. This is part of what can be considered to be secondary benefits of the EC carbon/energy tax.  相似文献   
19.
亚洲石油大陆桥建设设想   总被引:1,自引:0,他引:1  
李岱 《经济地理》1996,16(3):52-56
本文提出了关于建设亚洲石油大陆桥设想的国际意义,以及我国参与建设的必要性,并构建了亚州石油大陆桥的基本框架,最后提出中国应采取的主要对策和措施.  相似文献   
20.
Without an international climate agreement, extraction of more natural gas could reduce emissions of CO2 as more clean natural gas may drive out dirty coal and oil. Using a computable equilibrium model for the Western European electricity and natural gas markets, we examine whether increased extraction of natural gas in Norway reduces global emissions of CO2. We find that both in the short run and in the long run total emissions are reduced if the additional quantity of natural gas is used in gas power production in Norway. If instead the additional quantity is exported directly, total emissions increase both in the short run and in the long run. However, if modest CO2-taxes are imposed, increased extraction of natural gas will reduce CO2 emissions also when the additional natural gas is exported directed.earlier version of this paper was presented at the 25th Annual IAEE International Conference in Aberdeen June 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