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   507篇
  免费   12篇
  国内免费   8篇
安全科学   32篇
废物处理   17篇
环保管理   59篇
综合类   64篇
基础理论   90篇
污染及防治   160篇
评价与监测   68篇
社会与环境   30篇
灾害及防治   7篇
  2023年   8篇
  2022年   28篇
  2021年   17篇
  2020年   12篇
  2019年   15篇
  2018年   23篇
  2017年   28篇
  2016年   33篇
  2015年   19篇
  2014年   18篇
  2013年   58篇
  2012年   29篇
  2011年   34篇
  2010年   33篇
  2009年   20篇
  2008年   15篇
  2007年   16篇
  2006年   21篇
  2005年   17篇
  2004年   5篇
  2003年   9篇
  2002年   11篇
  2001年   1篇
  2000年   2篇
  1999年   3篇
  1998年   6篇
  1997年   3篇
  1996年   3篇
  1993年   5篇
  1992年   1篇
  1991年   4篇
  1989年   1篇
  1988年   1篇
  1987年   2篇
  1986年   2篇
  1985年   1篇
  1984年   2篇
  1983年   1篇
  1982年   3篇
  1981年   6篇
  1978年   2篇
  1977年   2篇
  1972年   2篇
  1968年   1篇
  1967年   1篇
  1965年   1篇
  1958年   1篇
  1957年   1篇
排序方式: 共有527条查询结果,搜索用时 15 毫秒
461.
462.
Environmental Science and Pollution Research - Three sampling campaigns were performed in the Lis River (Leiria, Portugal) in February of 2018, November of 2018, and May of 2019. River water and...  相似文献   
463.
Environmental Science and Pollution Research - The purpose of this research examination is to ascertain the effect of climate change, measured rainfall, temperature, and CO2, on crop production by...  相似文献   
464.
Louw R  Ahonkhai SI 《Chemosphere》2002,46(9-10):1273-1278
Pathways from chlorinated phenols as precursors to PCDD/Fs are discussed with focus on the effect of (poly)chlorination on thermochemistry and rate in the displacement of chlorine from a chlorophenol molecule by a (chloro)phenoxy radical (reaction (A) as a key example). Through measurements on the respective methylethers (anisoles) the O-H bond of 2,4,6-TCP turns out to be 5 kcal/ mol, and that in PCP 4 kcal/mol, less strong than O-H in phenol itself. On this basis it is concluded that-in contrast with earlier proposals--displacements such as in reaction (A) are at least as slow as reaction (B) of phenoxy radical with chlorobenzene. PhO. + PhCl -->PhOPh + Cl. reaction B Compared with condensation of two (chloro)phenoxy radicals, such radical/molecule reactions are therefore an insignificant pathway to dioxins in incinerators.  相似文献   
465.
In the Appalachian region of the eastern United States, mountaintop removal mining (MTM) is a dominant driver of land‐cover change, impacting 6.8% of the largely forested 4.86 million ha coal fields region. Recent catastrophic flooding and documented biological impairment downstream of MTM has drawn sharp criticism to this practice. Despite its extent, scale, and use since the 1970s, the impact of MTM on hydrology is poorly understood. Therefore, the goal of this study was a multiscale evaluation to establish the nature of hydrologic impacts associated with MTM. To quantify the extent of MTM, land‐cover change over the lifetime of this practice is estimated for a mesoscale watershed in southern West Virginia. To assess hydrologic impacts, we conducted long‐term trend analyses to evaluate for systematic changes in hydrology at the mesoscale, and conducted hydrometric and response time modeling to characterize storm‐scale responses of a MTM‐impacted headwater catchment. Results show a general trend in the conversion of forests to mines, and significant decreases in maximum streamflow and variability, and increases in base‐flow ratio attributed to valley fills and deep mine drainage. Decreases in variability are shown across spatial and temporal scales having important implications for water quantity and quality. However, considerable research is necessary to understand how MTM impacts hydrology. In an effort to inform future research, we identify existing knowledge gaps and limitations of our study.  相似文献   
466.
Since 1991, there have been significant changes in utilization of feed resources in the Ethiopian highlands: while use of communal grazing lands and private pastures has declined, use of crop residues and purchased feed has increased. In addition, although use of animal health services and adoption of improved livestock breeds and modern management practices have increased, ownership of various types of livestock has declined. Rapid population growth has contributed most to the declining trends in grazing resources and ownership of livestock, showing the negative effects of increasing pressure on already degraded resources in the Ethiopian highlands. Land redistribution, increased participation in credit and extension programs targeting livestock, and improvement in access to markets, on the other hand, have had significant positive impacts on adoption of improved livestock technologies and ownership of livestock. Thus, reducing population growth and improving access to markets and credit and extension programs targeting livestock can enhance the role of livestock in improving food security and reducing poverty, especially in the mixed crop-livestock farming systems as exist in the East African highlands.  相似文献   
467.
Environmental Science and Pollution Research - Removal of cationic dye, Azur II, and anionic dye, Reactive Red 2 (RR-2) from aqueous solutions, has been successfully achieved by using a modified...  相似文献   
468.
A method based on micellar liquid chromatography has been developed to simultaneously monitor four pesticides largely post-harvest applied to citrus:thiabendazole,pyrimethanil,o-phenylphenol and imazalil.Water samples were filtered and directly injected without other treatment,thus avoiding extraction steps.The composition of the mobile phase was optimized using a chemometrical approach to achieve and excellent resolution to 0.07 mol/L SDS/5%,V/V 1-pentanol buffered at p H 3.Mobile phase run through a C18 column at 1 m L/min at room temperature.The detection was performing by UV–Visible absorbance using a wavelength program:0–10 min,305 nm(for thiabendazole);10–12;265 nm(for pyrimethanil)and 12–18,220 nm(o-phenylphenol and imazalil).The developed method was validated following the guidelines of the US Environmental Protection Agency in terms of:quantitation range,(0.5–4 to 15μg/m L),linearity(r20.9995),sensitivity(LOD,0.18–1.4μg/m L),precision(9.2%),trueness(93.9%–103.7%),and ruggedness(9.9%).It was found that the fungicides remain up to eight days in surface water at outdoor conditions.The method was used to screen the presence of the analytes in several waste water samples,and was proved to be useful in routine analysis.  相似文献   
469.
Environment, Development and Sustainability - Siting of buildings in rural urban development requires that the prevalence of termite activities is considered. The severity of termite activities...  相似文献   
470.
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