全文获取类型
收费全文 | 1206篇 |
免费 | 108篇 |
国内免费 | 538篇 |
专业分类
安全科学 | 86篇 |
废物处理 | 77篇 |
环保管理 | 100篇 |
综合类 | 778篇 |
基础理论 | 225篇 |
环境理论 | 1篇 |
污染及防治 | 458篇 |
评价与监测 | 60篇 |
社会与环境 | 28篇 |
灾害及防治 | 39篇 |
出版年
2023年 | 24篇 |
2022年 | 43篇 |
2021年 | 40篇 |
2020年 | 37篇 |
2019年 | 33篇 |
2018年 | 38篇 |
2017年 | 42篇 |
2016年 | 58篇 |
2015年 | 69篇 |
2014年 | 107篇 |
2013年 | 111篇 |
2012年 | 102篇 |
2011年 | 116篇 |
2010年 | 97篇 |
2009年 | 105篇 |
2008年 | 137篇 |
2007年 | 87篇 |
2006年 | 105篇 |
2005年 | 69篇 |
2004年 | 66篇 |
2003年 | 61篇 |
2002年 | 57篇 |
2001年 | 34篇 |
2000年 | 35篇 |
1999年 | 29篇 |
1998年 | 36篇 |
1997年 | 23篇 |
1996年 | 30篇 |
1995年 | 19篇 |
1994年 | 7篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 8篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1983年 | 3篇 |
排序方式: 共有1852条查询结果,搜索用时 15 毫秒
71.
72.
城市有机垃圾间歇厌氧消化pH控制动力学研究 总被引:3,自引:0,他引:3
对厌氧消化系统的物料及电离平衡进行分析,利用底物降解和微生物生长动力学建立城市有机垃圾间歇厌氧消化pH值控制模型,并研制开发了间歇厌氧消化过程pH值与产气量最优化计算机软件.运用该模型可预测不同厌氧消化过程的最佳pH值,从而通过控制厌氧系统的pH值使系统产气量达到最大,通过2组对比实验验证模型的有效性.结果表明,在相同的实验条件下厌氧系统的pH控制在最佳值时系统产气较未对pH值控制时稳定,且总产气量平均提高20%左右. 相似文献
73.
Ling R. Zeng Li H. Shi Xin G. Meng J. Xu Gui F. Jia T. Gui 《Journal of environmental science and health. Part. B》2019,54(4):317-325
This study evaluated the hydrolysis and photolysis kinetics of pyraclostrobin in an aqueous solution using ultra-high-performance liquid chromatography–photodiode array detection and identified the resulting metabolites of pyraclostrobin by hydrolysis and photolysis in paddy water using high-resolution mass spectrometry coupled with liquid chromatography. The effect of solution pH, metal ions and surfactants on the hydrolysis of pyraclostrobin was explored. The hydrolysis half-lives of pyraclostrobin were 23.1–115.5?days and were stable in buffer solution at pH 5.0. The degradation rate of pyraclostrobin in an aqueous solution under sunlight was slower than that under UV photolysis reaction. The half-lives of pyraclostrobin in a buffer solution at pH 5.0, 7.0, 9.0 and in paddy water were less than 12?h under the two light irradiation types. The metabolites of the two processes were identified and compared to further understand the mechanisms underlying hydrolysis and photolysis of pyraclostrobin in natural water. The extracted ions obtained from paddy water were automatically annotated by Compound Discoverer software with manual confirmation of their fragments. Two metabolites were detected and identified in the pyraclostrobin hydrolysis, whereas three metabolites were detected and identified in the photolysis in paddy water. 相似文献
74.
75.
76.
预处理后的活性污泥对锌吸附的研究 总被引:2,自引:0,他引:2
剩余活性污泥处理是当今的热点问题,从活性污泥资源化的角度出发,将活性污泥加工成为锌离子的生物吸附剂,比较了8种方法预处理后的活性污泥对锌的吸附效果,分析了这8种方法对污泥吸附能力的影响机理.对经过NaOH和H2O2处理的污泥的吸附特性和影响因素进行了研究,结果表明该吸附过程符合Psemio-seconal Order吸附动力学模型及Freunomch吸附等温模型,低pH不利于吸附,适当提高温度可以增强吸附效果,增加污泥吸附剂浓度可以增加金属离子去除率,但是单位质量吸附剂吸附金属离子的量减小.用红外光谱对比的手段对吸附机理进行了探讨,结果表明污泥颗粒表面一些含氮氧的基团对zn.'的络合作用是主要的吸附机理.该研究在污泥资源化和废水中锌离子的去除方面有重要意义. 相似文献
77.
China is now facing huge pressure from both the domestic concern of energy security and the global community's call for emission reduction commitment. As one of the major energy consumers and greenhouse gas emitters, China's iron and steel industry has a huge clean development mechanism (CDM) potential. This article both quantitatively and qualitatively analyzes the current status of CDM project activities in the iron and steel industry in China, including characteristics of approved project types, applicable methodologies, and potential technology fields. From the perspective of project implementation, the article summarizes development barriers such as high investment risk, difficulty in project identification, strict requirements on PPDs, long registration waiting time, and etc. Policy suggestions are also put forwarded to help better promote the development of CDM projects in the iron and steel industry. 相似文献
78.
79.
Ying Guo Huan-Yun Yu Eddy Y. Zeng 《Environmental pollution (Barking, Essex : 1987)》2009,157(6):1753-1763
This review summarizes and analyzes available data in the literature (mostly after 2000) on the occurrence of dichlorodiphenyltrichloroethane (DDT) and its main metabolites, dichlorodiphenyldichloroethane (DDD) and chlorodiphenyldichloroethylene (DDE), in the environment of the Pearl River Delta (PRD), South China. Generally, the concentration levels of the sum of DDT, DDD, and DDE, designated as DDTs thereafter, have not significantly declined since 1983. However, the composition of DDTs residues has changed with time. DDTs in soil, freshwater sediment and freshwater fish species were mainly residues from chronological use. There is evidence that new point sources, such as dicofol and anti-fouling paint, may have contributed DDTs to various environmental compartments. Risk assessment against existing criteria indicated that the levels of DDTs in water and some fish species may pose adverse effects to humans or wildlife, and those in sediment/soil may also cause negative impacts to the eco-environment of the PRD. 相似文献
80.
碳羟基磷灰石对水中Cr(Ⅵ)的吸附性能研究 总被引:2,自引:0,他引:2
利用废弃蛋壳为原材料,水热法合成碳羟基磷灰石(CHAP),并利用X射线衍射、扫描电镜、能谱分析手段对其结构进行了表征.将CHAP作为含铬废水的吸附剂,考察了pH、Cr(Ⅵ)初始浓度、吸附时间等对Cr(Ⅵ)吸附行为的影响.结果表明,初始质量浓度为50 mg/L的Cr(Ⅵ)溶液,在常温(22±2) ℃、溶液pH为3.0、CHAP用量为5 g/L时,30 min基本达到吸附平衡,Cr(Ⅵ)去除率为98.3%,饱和吸附容量达29.85 mg/g.CHAP对Cr(Ⅵ)的吸附行为符合Langmuir吸附等温式和Freundlich吸附等温式,相关系数分别为0.998 4和0.922 6.通过10%(体积分数)H2SO4对吸附Cr(Ⅵ)的CHAP进行再生,再生率最高达95.8%. 相似文献