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   1261篇
  免费   51篇
  国内免费   14篇
安全科学   44篇
废物处理   62篇
环保管理   321篇
综合类   123篇
基础理论   317篇
环境理论   1篇
污染及防治   317篇
评价与监测   87篇
社会与环境   42篇
灾害及防治   12篇
  2023年   8篇
  2022年   8篇
  2021年   12篇
  2020年   18篇
  2019年   8篇
  2018年   23篇
  2017年   32篇
  2016年   44篇
  2015年   35篇
  2014年   38篇
  2013年   131篇
  2012年   51篇
  2011年   60篇
  2010年   48篇
  2009年   53篇
  2008年   66篇
  2007年   67篇
  2006年   69篇
  2005年   50篇
  2004年   40篇
  2003年   48篇
  2002年   45篇
  2001年   26篇
  2000年   33篇
  1999年   17篇
  1998年   21篇
  1997年   20篇
  1996年   24篇
  1995年   21篇
  1994年   21篇
  1993年   11篇
  1992年   14篇
  1991年   11篇
  1990年   7篇
  1989年   15篇
  1988年   10篇
  1987年   19篇
  1986年   9篇
  1985年   10篇
  1984年   8篇
  1983年   10篇
  1982年   14篇
  1981年   6篇
  1980年   4篇
  1979年   8篇
  1978年   5篇
  1977年   3篇
  1971年   3篇
  1967年   4篇
  1963年   2篇
排序方式: 共有1326条查询结果,搜索用时 46 毫秒
1.
2.
3.
4.
Two synthetic superabsorbent crosslinked acrylic polymers were mineralized by the white-rot fungusPhanerochaete chrysosporium. The amount of polymer converted to CO2 increased as the amount of polymer added to the cultures increased. In the presence of sufficiently large amounts of the superabsorbents, such that all of the culture fluid was absorbed and a gelatinous matrix was formed, the fungus still grew and mineralization was observed. Neither the polymers, nor their degradation products were toxic to the fungus. While the rates of mineralization were low, all of the polymers incubated in the liquid fungal cultures were completely depolymerized to water soluble products within 15–18 days. The depolymerization of the polymers was observed only in nitrogen limited cultures of the fungus which secrete the lignin degradation system, however, the water soluble products of depolymerization were mineralized in both nutrient limited and sufficient cultures of the fungus. The rate of mineralization of the depolymerized metabolites was more than two times greater in nutrient sufficient cultures. Following longer incubation periods, most (> 80 %) of the radioactivity was recovered in the fungal mycelial mat suggesting that carbon of the polymer had been converted to fungal metabolites.  相似文献   
5.
6.
7.
8.
9.
10.
Summary As stated at the beginning of this paper conclusions reached thus far cannot be discussed in this paper. However, a great deal of information is available for examination.EPA displayed its ability to coordinate widely separated laboratories, both Federal and private, into a smooth working team in a very short period of time. A very comprehensive study plan was also developed and implemented quickly. EPA was fortunate to have already had GCA under contract when the emergency arose. In no small part the success of the field effort was due to the managerial and technical abilities of the GCA team.Within a period of 6 weeks a plan was developed, a prime contractor retained, subcontractors hired, and field activities begun. Within a period of 3 months in excess of 8600 field samples were collected and over 12,000 field and QC samples were analyzed. During this same period 2 major data systems were developed, debugged, and placed into operation.In short this EPA project was probably the most comprehensive multimedia field project ever attempted by EPA and certainly the data is being subjected to the most strenuous quality control measures ever imposed by this Agency. The entire program is presently under peer review and the results are being prepared for publication by EPA Headquarters.Note. Originally intended to be published as part of the special issue on Exposure Monitoring: An International Workshop (Las Vegas, Nevada, October 19–22, 1981).  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