全文获取类型
收费全文 | 1620篇 |
免费 | 65篇 |
国内免费 | 717篇 |
专业分类
安全科学 | 120篇 |
废物处理 | 92篇 |
环保管理 | 132篇 |
综合类 | 943篇 |
基础理论 | 299篇 |
污染及防治 | 643篇 |
评价与监测 | 49篇 |
社会与环境 | 45篇 |
灾害及防治 | 79篇 |
出版年
2024年 | 4篇 |
2023年 | 28篇 |
2022年 | 84篇 |
2021年 | 70篇 |
2020年 | 49篇 |
2019年 | 38篇 |
2018年 | 58篇 |
2017年 | 76篇 |
2016年 | 99篇 |
2015年 | 95篇 |
2014年 | 133篇 |
2013年 | 159篇 |
2012年 | 156篇 |
2011年 | 128篇 |
2010年 | 116篇 |
2009年 | 113篇 |
2008年 | 128篇 |
2007年 | 108篇 |
2006年 | 90篇 |
2005年 | 77篇 |
2004年 | 34篇 |
2003年 | 60篇 |
2002年 | 59篇 |
2001年 | 49篇 |
2000年 | 48篇 |
1999年 | 58篇 |
1998年 | 53篇 |
1997年 | 43篇 |
1996年 | 39篇 |
1995年 | 38篇 |
1994年 | 22篇 |
1993年 | 25篇 |
1992年 | 20篇 |
1991年 | 14篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
排序方式: 共有2402条查询结果,搜索用时 5 毫秒
371.
372.
以磷钨酸为光催化剂,在紫外灯照射下,对甲基橙溶液进行光催化降解,考察了几种阴阳离子对磷钨酸光催化降解甲基橙溶液的影响。结果表明:Mg^2+、Ca^2+、NO3^-、SO4^2-和CO3^2-均对催化活性有促进作用,其中Mg^2+和Ca^2+仅有微弱的促进作用;NO3^-和SO4^2-随着浓度的增加促进作用也有所增加;CO3^2-则随着浓度的增加促进作用呈下降趋势;Mn^2+、Al^3+和Cl^-对光解反应存在较强的抑制作用,且Al^3+和Cl^-随着其浓度的增加,抑制作用增强。 相似文献
373.
374.
375.
人工湿地污水处理系统中植物体系的构建与展望 总被引:2,自引:0,他引:2
植物是人工湿地系统中的重要组成成分之一,它不仅可以起到净化污水的作用,而且还为微生物提供生存环境,同时具有景观价值。因此要选择适应性强、生物量大、根系发达、具有抗逆性的植物作为湿地植物。由于陆生植物受季节影响小且易于管理,超富集植物和转基因植物具有较高的吸收、吸附和富集的作用的特点相继成为湿地系统中植物研究的热点。而且通过合理配置植物系统可以提高湿地系统净化效果。湿地植物仍存在受季节变化的影响,植物的衰退,植物收割的后续处理等问题,仍有待研究。随着对湿地植物研究的深入,人工湿地系统一定会获得更加广阔的应用前景。 相似文献
376.
解薇 《防灾科技学院学报》2008,10(3)
四川汶川地震突如其来,它在造成物质毁坏的同时,也给人的心理,特别是对未成年人造成极大的创伤。本文从地震对未成年人造成的心理伤害的内容解析出发,研究了震后未成年人急性应激反应和创伤后应激障碍,并结合地震灾害救灾实际,设计了地震灾害心理救助 相似文献
377.
378.
Abstract There is an obvious departure from the regional equilibrium of developments between the upper and lower reaches of the Pearl River in Guangdong, which resulted in “the effects of contra-geography-grads development”. It is mainly because the upriver mountainous areas have been deeply stuck in industrialization delay and marginalization plights, so that nearly 40 million local people have conceived a dream to get rid of “the vicious circle of poverty” by speeding up industrial development. But the problem is that such industrialization efforts on a large scale in mountainous areas are encountering the bottleneck of environmental capacity that strictly limits industrial emissions along the upper reaches of any water system. As a solution, an institutional arrangement called “the Local Area Quotas for Industrial Emis-sions along the Pearl River” is put forward supposed to give corresponding compensation to the rights of industrial development yielded by some areas with lower environmental capacity through the distribution and trading of IDQs. 相似文献
379.
Forest certification is a mechanism involving the regulation of trade of forest products in order to protect forest resources
and improve forest management. Although China had a late start in adopting this process, the country has made good progress
in recent years. As of July 31, 2009, 17 forest management enterprises and more than one million hectares of forests in China
have been certified by the Forest Stewardship Council (FSC). Several major factors affect forest certification in China. The
first set is institutional in nature. Forest management in China is based on centralized national plans and therefore lacks
flexibility. A second factor is public awareness. The importance and value of forest certification are not widely understood
and thus consumers do not make informed choices regarding certified forest products. The third major factor is the cost of
certification. Together these factors have constrained the development of China’s forest certification efforts. However, the
process does have great potential. According to preliminary calculations, if 50% of China’s commercial forests were certified,
the economic cost of forest certification would range from US$0.66–86.63 million while the economic benefits for the forestry
business sector could exceed US$0.66–86.63 million while the economic benefits for the forestry
business sector could exceed US150 million. With continuing progress in forest management practices and the development of
international trade in forest products, it becomes important to improve the forest certification process in China. This can
be achieved by improving the forest management system, constructing and perfecting market access mechanisms for certificated
forest products, and increasing public awareness of environmental protection, forest certification, and their interrelationship. 相似文献
380.
Anping Zhang Xuemei Xie Jing Ye Chunmian Lin Xiaoyan Hu 《Environmental Chemistry Letters》2011,9(3):369-373
In recent years, the stereoselective toxicity of chiral organophosphorus pesticides has received increasing attention from
environmental toxicology scientists. In an attempt to explore the stereoselective effects of chiral organophosphorus pesticides
on non-target organisms and enzymes, this work investigated the stereoselective toxicity and inhibition of malathion, malaoxon
and isomalathion on Daphnia magna and on acid α-naphthyl acetate esterase extracted from wheat flour, respectively. Toxicity differences were observed between
the two enantiomers of malathion and malaoxon and among the four stereoisomers of isomalathion in the LC50 values on D. magna and the IC50 values on acid α-naphthyl acetate esterase. Enantiomers with (R)-configuration in all the tested compounds showed
higher toxicity to D. magna than their (S)-forms and racemic forms. Racemic malaoxon and isomalathion showed the strongest inhibition on acid α-naphthyl
acetate esterase compared to their respective enantiomers and stereoisomers. 相似文献