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   175篇
  免费   48篇
  国内免费   50篇
大气科学   12篇
地球物理   83篇
地质学   101篇
海洋学   20篇
天文学   20篇
综合类   6篇
自然地理   31篇
  2023年   1篇
  2022年   4篇
  2020年   3篇
  2019年   4篇
  2018年   8篇
  2017年   8篇
  2016年   10篇
  2015年   8篇
  2014年   12篇
  2013年   10篇
  2012年   14篇
  2011年   10篇
  2010年   10篇
  2009年   11篇
  2008年   22篇
  2007年   6篇
  2006年   11篇
  2005年   10篇
  2004年   3篇
  2003年   10篇
  2002年   7篇
  2001年   11篇
  2000年   8篇
  1999年   10篇
  1998年   9篇
  1997年   7篇
  1996年   7篇
  1995年   11篇
  1994年   8篇
  1993年   8篇
  1992年   2篇
  1991年   2篇
  1989年   4篇
  1988年   3篇
  1985年   1篇
排序方式: 共有273条查询结果,搜索用时 62 毫秒
271.
272.
Application of Some Complexing Ion Exchangers for Copper Recovery from Natural Water and Wastewater The rational use of water resources is one of the urgent environmental control problems. These problems can be solved by the treatment of sewage. Removal of different non‐ferrous heavy metal ions from wastewater is of great importance. Besides, the selective complexing ion exchangers are of interest because of their good sorption properties. The present paper is devoted to the study of some complexing resins for copper recovery from natural water and sewage. The following carboxylic resins were studied: the cation exchangers KB‐2T, KB‐4 and the amphoteric ion exchangers ANKB 35, AMF‐2T, and AMF‐2S (manufacturer – “TOKEM” company, Kemerovo, Russia). The exchangers investigated differed from each other both by their functional groups and by their matrix physical structures. The copper recovery from CuCl2‐, CuSO4‐, and Cu(NO3)2‐solutions was studied in batch‐experiments (in presence of NaCl, Na2SO4, and NaNO3). The initial copper concentration in the solutions was 0.0002...0.008 mol/L; pH values were 1.0...5.0. After equilibrium (24 h) the resins were separated from the solution. The copper concentration in the solutions after the sorption was determined by the photometrical method with pyridylazoresorcin (λ = 500 nm). On the basis of the experimental data distribution ratio, the separation factors, equilibrium constants, and stability constants of copper complexes in the exchanger phase were calculated. It was found out in this work that the amphoteric ion exchanger AMF‐2T of macroreticular structure is the most effective for the copper sorption from sewage.  相似文献   
273.
A characterization method for AOX in surface water samples was developed and tested. The method involves fractionation using a hydrophobic C18 resin and a weak anionic exchange resin and allows the fractionation of the AOX pool of surface water samples into four fractions: (1) hydrophilic acidic, (2) hydrophilic non‐acidic, (3) hydrophobic acidic, and (4) hydrophobic non‐acidic. The adsorption analysis was verified with AOX‐relevant model compounds and was applied to characterize the AOX pool of a stream sample from the Moskva river (Russia). In addition to the fractionation analysis, size‐exclusion chromatography was used to characterize the AOX pool of the sample studied. Hydrophilic acids made up the major fraction of the AOX pool (55 %). Among this fraction chlorinated high‐molecular acids (humic substances) made up the main fraction (35 %).  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