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   71583篇
  免费   710篇
  国内免费   803篇
安全科学   2059篇
废物处理   3329篇
环保管理   9685篇
综合类   10874篇
基础理论   19684篇
环境理论   45篇
污染及防治   17712篇
评价与监测   5095篇
社会与环境   4132篇
灾害及防治   481篇
  2022年   576篇
  2021年   609篇
  2020年   457篇
  2019年   562篇
  2018年   2176篇
  2017年   2108篇
  2016年   2452篇
  2015年   1254篇
  2014年   1698篇
  2013年   5160篇
  2012年   2442篇
  2011年   3881篇
  2010年   2903篇
  2009年   2810篇
  2008年   3465篇
  2007年   3829篇
  2006年   2595篇
  2005年   2181篇
  2004年   2161篇
  2003年   2168篇
  2002年   2042篇
  2001年   2480篇
  2000年   1762篇
  1999年   1115篇
  1998年   866篇
  1997年   835篇
  1996年   874篇
  1995年   933篇
  1994年   908篇
  1993年   791篇
  1992年   791篇
  1991年   742篇
  1990年   783篇
  1989年   769篇
  1988年   676篇
  1987年   599篇
  1986年   515篇
  1985年   571篇
  1984年   610篇
  1983年   625篇
  1982年   622篇
  1981年   542篇
  1980年   451篇
  1979年   507篇
  1978年   445篇
  1977年   357篇
  1976年   350篇
  1975年   340篇
  1974年   315篇
  1972年   332篇
排序方式: 共有10000条查询结果,搜索用时 447 毫秒
821.
822.
823.
824.
825.
826.
827.
828.
829.
This paper describes a method for determining reductions of SO2 emissions from coal- and oil-fired power stations, oil refineries and large industrial units in the UK taking into account their pollution potential. The method is based on the use of two gridded data sets: critical loads, which represent the sensitivity of the environment to acid deposition and modelled estimates of total (wet + dry) sulphur deposition for 646 point sources within the UK. An iterative method is used to identify and subsequently reduce emissions from point sources that contribute most to areas of critical loads exceedance. This paper demonstrates how the method may be used to determine an optimal allocation of emissions across the UK which yields the maximum amount of environmental protection per unit of emission.The paper then goes on to consider the changes that will have to take place within the UK power generation industry in order to meet the revised EC Large Combustion Plant Directive which comes into force on 1 January 2008. Particular emphasis is placed upon proposed emissions trading schemes and the environmental implications of allowing trading between stations with high and low pollution potentials. The paper concludes by suggesting that the emissions trading process should take into account the pollution potential of each source, irrespective of whether the proposed emission is within the plant's agreed emission limit. An approach based entirely on minimizing environmental damage rather than one which takes cost into account, as in current integrated assessment modelling, could provide an interesting approach across the rest of Europe.  相似文献   
830.
The rate of carbon accumulation in the atmosphere can be reduced by decreasing emissions from the burning of fossil fuels and by increasing the net uptake (or reducing the net loss) of carbon in terrestrial (and aquatic) ecosystems. The Kyoto Protocol addresses both the release and uptake of carbon. Canada is developing a National Forest Carbon Monitoring, Accounting and Reporting System in support of its international obligations to report greenhouse gas sources and sinks. This system employs forest-inventory data, growth and yield information, and statistics on natural disturbances, management actions and land-use change to estimate forest carbon stocks, changes in carbon stocks, and emissions of non-CO2 greenhouse gases. A key component of the system is the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS). The model is undergoing extensive revisions to enable analyses at four spatial scales (national, provincial, forest management unit and stand) and in annual time steps. The model and the supporting databases can be used to assess carbon-stock changes between 1990 and the present, and to predict future carbon-stock changes based on scenarios of future disturbance rates and management actions.  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