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   442篇
  免费   2篇
  国内免费   3篇
安全科学   2篇
废物处理   19篇
环保管理   34篇
综合类   220篇
基础理论   68篇
污染及防治   70篇
评价与监测   18篇
社会与环境   15篇
灾害及防治   1篇
  2020年   4篇
  2018年   8篇
  2017年   7篇
  2016年   4篇
  2015年   6篇
  2014年   15篇
  2013年   13篇
  2012年   14篇
  2011年   13篇
  2010年   18篇
  2009年   11篇
  2008年   20篇
  2007年   18篇
  2006年   13篇
  2005年   8篇
  2004年   14篇
  2003年   8篇
  2002年   14篇
  2001年   6篇
  2000年   6篇
  1999年   4篇
  1997年   6篇
  1995年   8篇
  1994年   5篇
  1993年   4篇
  1992年   5篇
  1983年   4篇
  1966年   5篇
  1964年   5篇
  1962年   5篇
  1961年   7篇
  1960年   9篇
  1959年   10篇
  1957年   8篇
  1956年   6篇
  1955年   7篇
  1954年   6篇
  1953年   3篇
  1952年   7篇
  1950年   5篇
  1948年   3篇
  1943年   3篇
  1942年   3篇
  1933年   5篇
  1932年   4篇
  1930年   4篇
  1929年   5篇
  1926年   3篇
  1924年   3篇
  1913年   4篇
排序方式: 共有447条查询结果,搜索用时 234 毫秒
81.
82.
83.
84.
85.
86.
87.
88.
International negotiations on the inclusion of land use activities into an emissions reduction system for the UN Framework Convention on Climate Change (UNFCCC) have been partially hindered by the technical challenges of measuring, reporting, and verifying greenhouse gas (GHG) emissions and the policy issues of leakage, additionality, and permanence. This paper outlines a five-part plan for estimating forest carbon stocks and emissions with the accuracy and certainty needed to support a policy for Reducing Emissions from Deforestation and forest Degradation, forest conservation, sustainable management of forests, and enhancement of forest carbon stocks (the REDD-plus framework considered at the UNFCCC COP-15) in developing countries. The plan is aimed at UNFCCC non-Annex 1 developing countries, but the principles outlined are also applicable to developed (Annex 1) countries. The parts of the plan are: (1) Expand the number of national forest carbon Measuring, Reporting, and Verification (MRV) systems with a priority on tropical developing countries; (2) Implement continuous global forest carbon assessments through the network of national systems; (3) Achieve commitments from national space agencies for the necessary satellite data; (4) Establish agreed-on standards and independent verification processes to ensure robust reporting; and (5) Enhance coordination among international and multilateral organizations.  相似文献   
89.
A novel gas purification system employing membrane contactors with dense membranes in the absorption as well as the desorption unit has been tested concerning the separation efficiency of CO2. The separation efficiency of potassium carbonate (K2CO3) promoted by piperazine (PZ) as absorption medium has been tested in the absorption unit. Since the absorbent will be regenerated in the desorption unit, the influence of temperature, sweep flow rate and absorbent type (0.5 M K2CO3 and 0.5 M K2CO3/0.5 M PZ) on the separation efficiency of CO2 in the desorption unit has been investigated. Desorption by vacuum has been considered as well.In addition experimental results of the coupling of a bioreactor producing hydrogen by anoxygenic photosynthesis (low and fluctuating product gas flow rates and fluctuating compositions) with a membrane contactor for gas purification are reported. This was done in order to show the applicability of this system to processes producing biogases.  相似文献   
90.
We consider contracting of a principal with an agent if multilateral externalities are present. The motivating example is that of an international climate agreement given private information about the willingness-to-pay (WTP) for emissions abatement. Due to multilateral externalities the principal uses her own emissions besides subsidies to incentivize the agent and to assure his participation. Optimal contracts equalize marginal abatement costs and, thus, can be implemented by a system of competitive permit trading. Moreover, optimal contracts can include a boundary part (i.e., the endogenous, type dependent participation constraint is binding), which is not a copy of the outside option of no contract. Compared to this outside option, a contract can increase emissions of the principal for types with a low WTP, and reduce her payoff for high types. Subsidies can be constant or even decreasing in emission reductions, and turn negative so that the agent reduces emissions and pays the principal.  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