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   581篇
  免费   49篇
  国内免费   722篇
安全科学   63篇
废物处理   4篇
环保管理   22篇
综合类   738篇
基础理论   464篇
污染及防治   22篇
评价与监测   17篇
社会与环境   10篇
灾害及防治   12篇
  2024年   3篇
  2023年   18篇
  2022年   16篇
  2021年   33篇
  2020年   25篇
  2019年   30篇
  2018年   23篇
  2017年   25篇
  2016年   28篇
  2015年   62篇
  2014年   128篇
  2013年   50篇
  2012年   52篇
  2011年   40篇
  2010年   30篇
  2009年   102篇
  2008年   92篇
  2007年   45篇
  2006年   17篇
  2005年   26篇
  2004年   13篇
  2003年   9篇
  2002年   9篇
  2001年   14篇
  2000年   4篇
  1999年   36篇
  1998年   56篇
  1997年   47篇
  1996年   58篇
  1995年   67篇
  1994年   51篇
  1993年   36篇
  1992年   22篇
  1991年   52篇
  1990年   2篇
  1989年   29篇
  1988年   1篇
  1987年   1篇
排序方式: 共有1352条查询结果,搜索用时 31 毫秒
281.
By analyzing the cases in Taishan Mountain, Shandong Province and other tourist sites in China, this paper pointed out the problems in tourism management, such as resources damage, environment pollution, which are the result of tourism development, and are obstacles to the development. The paper also gave suggestion and practical ways to preserve tourism resources and environment.  相似文献   
282.
The paper presented the results regarding the decomposition of gaseous CF2ClBr by cold plasma method.After two minutes discharge,the maximum decomposition rate of 2660 Pa CF2ClBr pure and 2660 Pa CF2ClBr plus 7980 Pa O2 reached 60% and 80%,respectively.The paper also studied the cold plasma gas phase chemistry reaction mechanism of CF2ClBr at low pressure,and the pressure effects of CF2ClBr and added gas(He,N2,O2 and dry air)on the CF2ClBr decomposition respectively by cold plasma method.These studies will be helpful to application of cold plasma method in the treatment of hazardous gaseous wastes.  相似文献   
283.
Characteristicsoffraileco-environmentinHebeiplateauSunJianzhong;YangMinghua;ShengXuebin;LiuQuanyou(ResearchCenterforEco-Envir...  相似文献   
284.
MonitoringofPotentialcarcinogenicpolycyclicaromaticcompoundsintheemissionfromcoalcombustionCuiWenxuan,YaoWeixi,XuXiaobai(Rese...  相似文献   
285.
FreradicaloxidationofspentradioactiveorganicsolventJiXiaoyuan,ZhaoBinInstituteofNuclearEnergyTechnology,TsinghuaUniversity,Be...  相似文献   
286.
QuantitativemodelforspeciesdistributionofhydroxypolyaluminumchlorideFengLi,LuanZhaokun,TangHongxiaoResearchCenterforEcoEnvir...  相似文献   
287.
Seasonal measurements of dimethylsulfide(DMS)in surface waters were carried out during 1993-1994 in the Jiaozhou Bay.A seasonal variation is observed for DMS concentrations in seawater,ranging from 0.6 to 8.97 nmol S/L with the highest values in spring.A factor of 4 was measured for DMS concentrations with mean concentrations of 5.85 nmol S/L or 6.58 nmol S/L in spring and 1.40nmol S/L in winter.A sea-to-air flux of DMS also showed a seasonal variation  相似文献   
288.
The carcinogenic antioxidants,N-phenyl-1-naphthylamine (P1NA)and N-phenyl-2-naphthylamine (P2NA) were examined in vitro for biotransformation by rat hepatic microsomes and in freshly isolated hepatocytes. HPLC-analysis of hepatocyte incubations with revealed that phenols were the major metabolites in both cases. P1NA formed one phenolic metabolite only, while incubation with P2NA yielded two phenols identified as 6-hydroxy-P2NA and 4'-hydroxy-P2NA by cochromatography with authentic samples. β-naphthylamine, a metabolite indicating dephenylation of P2NA was not detectable.Metabolism studies with microsomes revealed that the phenols were formed by cytochrome P-450 dependent monooxygenases. Pretreatment of animals with phenobarbital and 3-methylcholanthrene both increased the rate of microsomal metabolism of P1NA and P2NA, indicating that more than one P-450 enzyme mediate the oxygenation reaction. Animal pretreatment with single and repeated doses of P1NA and P2NA did not markedly stimulate metabolism, b  相似文献   
289.
A procedure for analysis of organic pollutants in coal gasification wastewater was developed, including a series extraction steps at different pH, followed by LC separation or resin adsorption, then analyzed by GC or GC/MS. More than 200 organic pollutants in 22 categories were determined. CH2CL2 extraction at NaHCO3 presence was used to separate carboxylic acids with phenolic compounds in aqueous. Derivatization with acetic anhydride was used for analyses of mono-, di-, poly-hydroxyl phenolic compounds. 21 mono-hydroxyl phenols and 13 di-hydroxyl phenols were determined from the coai gasification wastewater samples. Derivatization with BF3-CH3OH was used for analysis of carboxylic acid. 17 mono-carboxyl, 4 di-carboxyl acids and 6 aromatic acids were determined from coal gasification wastewater samples.  相似文献   
290.
TheeffectoflightontheMn(II)orFetlll)xatalyzedoxidationofaqueousS(IV)XuYongfu(InstituteofAtmosphericPhysics,ChineseAcademyofSc...  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