全文获取类型
收费全文 | 2727篇 |
免费 | 244篇 |
国内免费 | 854篇 |
专业分类
安全科学 | 265篇 |
废物处理 | 157篇 |
环保管理 | 208篇 |
综合类 | 1710篇 |
基础理论 | 396篇 |
环境理论 | 1篇 |
污染及防治 | 540篇 |
评价与监测 | 185篇 |
社会与环境 | 196篇 |
灾害及防治 | 167篇 |
出版年
2024年 | 9篇 |
2023年 | 58篇 |
2022年 | 191篇 |
2021年 | 144篇 |
2020年 | 144篇 |
2019年 | 115篇 |
2018年 | 154篇 |
2017年 | 145篇 |
2016年 | 128篇 |
2015年 | 159篇 |
2014年 | 244篇 |
2013年 | 213篇 |
2012年 | 203篇 |
2011年 | 195篇 |
2010年 | 182篇 |
2009年 | 181篇 |
2008年 | 155篇 |
2007年 | 161篇 |
2006年 | 133篇 |
2005年 | 78篇 |
2004年 | 113篇 |
2003年 | 108篇 |
2002年 | 129篇 |
2001年 | 121篇 |
2000年 | 93篇 |
1999年 | 79篇 |
1998年 | 41篇 |
1997年 | 29篇 |
1996年 | 32篇 |
1995年 | 23篇 |
1994年 | 22篇 |
1993年 | 15篇 |
1992年 | 4篇 |
1991年 | 9篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有3825条查询结果,搜索用时 218 毫秒
991.
992.
In this study, a novel horizontal rotating soil washing process and equipment were developed and tested for pilot-scale remediation of soils from a site polluted by chromium ore process residue. Operating parameters, including cylinder rotational velocity, cylinder tilt angle, heating temperature and liquid/soil ratio, were investigated. The Taguchi method was used for the experiment design, and the standard L16 orthogonal array with four parameters and four levels was selected for optimising the operating parameters. Optimal removal efficiency was achieved at cylinder rotational velocity of 2.5 rpm, cylinder tilt angle of 2.6°, heating temperature of 200 °C and liquid/soil ratio of 8. The efficiency of citric acid as an extractant in the novel process was compared with that of water. The analysis of the residual Cr(VI) concentration of the soil shows that citric acid could efficiently remove 22.89 % more Cr(VI) than water in one-stage washing. The residual Cr(VI) concentration in the soil after the three-stage washing is as low as 26.16 mg/kg, which meets the screening levels for soil environmental risk assessment of sites in Beijing City (30 mg/kg). Further study is currently underway to optimise the novel process and equipment for commercial-scale use. 相似文献
993.
994.
995.
Hua Fang Yun L. Yu Xiu G. Wang Xiao Q. Chu Xiao E. Yang 《Journal of environmental science and health. Part. B》2013,48(2):123-129
Effects of repeated applications of the herbicide butachlor (N-(butoxymethyl)-2-chloro -N-2′,6′-dimethyl acetanilide) in soil on its persistence and soil microbial functional diversity were investigated under laboratory conditions. The degradation half-lives of butachlor at the recommended dosage in soil were calculated to be 12.5, 4.5, and 3.2 days for the first, second, and third applications, respectively. Throughout this study, no significant inhibition of the Shannon-Wiener index H′ was observed. However, the Simpson index 1/D and McIntosh index U were significantly reduced (P ≤ 0.05) during the initial 3 days after the first application of butachlor, and thereafter gradually recovered to a similar level to that of the control soil. A similar variation but faster recovery in 1/D and U was observed after the second and third Butachlor applications. Therefore, repeated applications of butachlor led to more rapid degradation of the herbicide, and more rapid recovery of soil microorganisms. It is concluded that repeated butachlor applications in soil had a temporary or short-term inhibitory effect on soil microbial communities. 相似文献
996.
We investigated the ecophysiology (physiological ecology) of plant succession within a coastal wetland community. The photosynthetic
characteristics of six plants were studied; Scirpus mariqueter and Carex scabrifolia in early successional communities, Phragmites communis and Tamarix chinensis in mid successional communities, and Salix matsudana and Imperata cylindrica in later successional communities. Environmental factors were concurrently determined for each community. Relationships between
photosynthetic and environmental factors were analyzed by path analysis, and the dependence of photosynthesis on particular
environmental factors was shown to vary between plants in the differing successional communities. Ability to cope with irradiation
appears to be one of the most important factors influencing plant succession. The increasing stratification of plant communities
following colonization of new coastal land necessitates differing physiological strategies and photosynthetic dynamics in
the later colonizing plants. 相似文献
997.
研究Pb-Cd复合污染对5种树木叶片的生理伤害和La-Gly-VB6对Pb-Cd污染胁迫的缓解作用。实验结果表明,La-Gly-VB6能明显减轻Pb-Cd污染造成的植物叶片叶绿素含量下降、质膜透性增加,过氧化氢酶活性改变和Pb富集量上升。说明La-Gly-VB6对Pb-Cd污染胁迫具有一定的防护作用。 相似文献
998.
999.
1000.