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   22805篇
  免费   207篇
  国内免费   372篇
安全科学   619篇
废物处理   1150篇
环保管理   2655篇
综合类   3167篇
基础理论   5875篇
环境理论   6篇
污染及防治   6365篇
评价与监测   1836篇
社会与环境   1574篇
灾害及防治   137篇
  2023年   110篇
  2022年   283篇
  2021年   259篇
  2020年   163篇
  2019年   216篇
  2018年   428篇
  2017年   373篇
  2016年   598篇
  2015年   427篇
  2014年   658篇
  2013年   1947篇
  2012年   746篇
  2011年   991篇
  2010年   905篇
  2009年   896篇
  2008年   1015篇
  2007年   1110篇
  2006年   972篇
  2005年   810篇
  2004年   814篇
  2003年   787篇
  2002年   743篇
  2001年   1063篇
  2000年   726篇
  1999年   439篇
  1998年   306篇
  1997年   280篇
  1996年   311篇
  1995年   299篇
  1994年   283篇
  1993年   266篇
  1992年   262篇
  1991年   224篇
  1990年   236篇
  1989年   237篇
  1988年   208篇
  1987年   169篇
  1986年   144篇
  1985年   149篇
  1984年   186篇
  1983年   167篇
  1982年   205篇
  1981年   149篇
  1980年   127篇
  1979年   159篇
  1978年   126篇
  1977年   115篇
  1976年   106篇
  1975年   93篇
  1974年   92篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
Environment, Development and Sustainability - Land use and land cover change (LULCC) is one of the problems that the world has been facing for the last few decades despite political attention....  相似文献   
102.
103.
104.
105.
106.

The combination of concentrated solar power–chemical looping air separation (CSP-CLAS) with an oxy-fuel combustion process for carbon dioxide (CO2) capture is a novel system to generate electricity from solar power and biomass while being able to store solar power efficiently. In this study, the computer program Advanced System for Process Engineering Plus (ASPEN Plus) was used to develop models to assess the process performance of such a process with manganese (Mn)-based oxygen carriers on alumina (Al2O3) support for a location in the region of Seville in Spain, using real solar beam irradiance and electricity demand data. It was shown that the utilisation of olive tree prunings (Olea europaea) as the fuel—an agricultural residue produced locally—results in negative CO2 emissions (a net removal of CO2 from the atmosphere). Furthermore, it was found that the process with an annual average electricity output of 18 MW would utilise 2.43% of Andalusia’s olive tree prunings, thereby capturing 260.5 k-tonnes of CO2, annually. Drawbacks of the system are its relatively high complexity, a significant energy penalty in the CLAS process associated with the steam requirements for the loop-seal fluidisation, and the gas storage requirements. Nevertheless, the utilisation of agricultural residues is highly promising, and given the large quantities produced globally (~?4 billion tonnes/year), it is suggested that other novel processes tailored to these fuels should be investigated, under consideration of a future price on CO2 emissions, integration potential with a likely electricity grid system, and based on the local conditions and real data.

  相似文献   
107.
108.
109.
The translocation of some heavy metals, such as Hg, Cd, Cu, Co, Ni and Zn, as affected by organic pollutants, i.e. methanol, ethanol, propanol, formaldehyde, acetaldehyde, benzaldehyde, acetone, ethyl methyl ketone and cyclo-hexanone, was studied in an Indian red soil using soil thin layer chromatography. It was observed that an increase in the concentration of organic compounds in developer enhances the heavy metal mobility, except in the case of Cu and Hg which show a decreasing trend. The results are discussed in relation to the physico-chemical characteristics of the soil and adsorption/desorption phenomena.  相似文献   
110.
Cultured oysters from Hiroshima Bay were analysed to determine the content of nine trace elements, cadmium (Cd), lead (Pb), chromium (Cr), arsenic (As), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), and iron (Fe) and compared with oysters treated for 48 h in both artificial sea water and a solution of 0.5% ethylenediaminetetraacetic acid (EDTA) in artificial sea water. It was found that the values of As and Fe in both groups of treated oysters were significantly lower than in the untreated oysters and that the Pb and Mn levels tended to be lower. It was also found that oysters treated in 0.5% EDTA solution in artificial sea water had lower levels of Cd and Cu than the oysters treated only in artificial sea water.  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