全文获取类型
收费全文 | 516篇 |
免费 | 9篇 |
国内免费 | 57篇 |
专业分类
安全科学 | 7篇 |
废物处理 | 22篇 |
环保管理 | 51篇 |
综合类 | 123篇 |
基础理论 | 117篇 |
污染及防治 | 172篇 |
评价与监测 | 69篇 |
社会与环境 | 18篇 |
灾害及防治 | 3篇 |
出版年
2023年 | 4篇 |
2022年 | 10篇 |
2021年 | 13篇 |
2020年 | 14篇 |
2019年 | 9篇 |
2018年 | 9篇 |
2017年 | 19篇 |
2016年 | 23篇 |
2015年 | 14篇 |
2014年 | 23篇 |
2013年 | 62篇 |
2012年 | 11篇 |
2011年 | 20篇 |
2010年 | 25篇 |
2009年 | 23篇 |
2008年 | 23篇 |
2007年 | 25篇 |
2006年 | 23篇 |
2005年 | 23篇 |
2004年 | 18篇 |
2003年 | 13篇 |
2002年 | 19篇 |
2001年 | 21篇 |
2000年 | 11篇 |
1999年 | 9篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 7篇 |
1995年 | 9篇 |
1994年 | 7篇 |
1993年 | 7篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1982年 | 5篇 |
1979年 | 2篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1971年 | 4篇 |
1966年 | 4篇 |
1965年 | 5篇 |
1964年 | 4篇 |
1963年 | 5篇 |
1961年 | 6篇 |
1960年 | 2篇 |
1958年 | 2篇 |
1955年 | 2篇 |
排序方式: 共有582条查询结果,搜索用时 187 毫秒
221.
天然有机物对零价铁去除水体中砷的影响研究 总被引:3,自引:0,他引:3
在研究零价铁对水体中砷去除动力学的基础上,着重探讨了天然有机物腐殖酸对零价铁除砷的影响.并对零价铁的腐蚀产物进行了分析.结果表明,水体中的砷可以通过在零价铁腐蚀产物上的吸附得到快速去除.腐殖酸显著降低了砷的去除率,这归因于腐殖酸与零价铁腐蚀产生的铁离子形成络合物,阻止了Fe(OH)3(或Fe(OH)2)沉淀的产生.腐殖酸浓度越高.砷的去除率越低.1.00 mg腐殖酸最多可以络合约0.75 mg铁离子.当铁离子与腐殖酸的络合达到饱和后,零价铁进一步腐蚀产生的铁离子可形成Fe(OH)3(或Fe(OH)2)沉淀,这些沉淀物可吸附水体中的腐殖酸和砷,从而加速砷的去除.冷冻干燥后的零价铁腐蚀产物的结构以无定型为主,含有少量的结晶化合物,包括γ-Fe2O3、γ-FeO(OH)和Fe3O4等.腐殖酸的存在可进一步增加腐蚀产物中的无定型成分.光电能谱(XPS)分析结果显示,吸附在腐蚀产物上的砷为5价,没有发现5价砷被还原成3价砷.在应用零价铁修复砷污染水体时,应考虑腐殖酸的影响. 相似文献
222.
Modeling watershed-scale effectiveness of agricultural best management practices to reduce phosphorus loading 总被引:1,自引:0,他引:1
Nalini S. Rao Zachary M. Easton Elliot M. Schneiderman Mark S. Zion David R. Lee Tammo S. Steenhuis 《Journal of environmental management》2009
Planners advocate best management practices (BMPs) to reduce loss of sediment and nutrients in agricultural areas. However, the scientific community lacks tools that use readily available data to investigate the relationships between BMPs and their spatial locations and water quality. In rural, humid regions where runoff is associated with saturation-excess processes from variable source areas (VSAs), BMPs are potentially most effective when they are located in areas that produce the majority of the runoff. Thus, two critical elements necessary to predict the water quality impact of BMPs include correct identification of VSAs and accurate predictions of nutrient reduction due to particular BMPs. The objective of this research was to determine the effectiveness of BMPs using the Variable Source Loading Function (VSLF) model, which captures the spatial and temporal evolutions of VSAs in the landscape. Data from a long-term monitoring campaign on a 164-ha farm in the New York City source watersheds in the Catskills Mountains of New York state were used to evaluate the effectiveness of a range of BMPs. The data spanned an 11-year period over which a suite of BMPs, including a nutrient management plan, riparian buffers, filter strips and fencing, was installed to reduce phosphorus (P) loading. Despite its simplicity, VSLF predicted the spatial distribution of runoff producing areas well. Dissolved P reductions were simulated well by using calibrated reduction factors for various BMPs in the VSLF model. Total P losses decreased only after cattle crossings were installed in the creek. The results demonstrated that BMPs, when sited with respect to VSAs, reduce P loss from agricultural watersheds, providing useful information for targeted water quality management. 相似文献
223.
Co-present Pb(II) accelerates the oxidation of organic contaminants by permanganate: Role of Pb(III)
Lei Dong Pin Xie Xin Zhang Junlian Qiao Dandan Rao Yuankui Sun Xiaohong Guan 《Frontiers of Environmental Science & Engineering》2022,16(8):109
224.
S. Saravanan G. Nagarajan G. Lakshmi Narayana Rao 《International Journal of Sustainable Engineering》2016,9(3):182-188
The main objective of this work is to control the NOx emission of a stationary diesel engine fuelled with crude rice bran oil methyl ester blend with less sacrifice on smoke density and brake thermal efficiency (BTE) and also to investigate the factors influencing the objective. Fuel injection timing, percentage of exhaust gas recirculation and fuel injection pressure are chosen as the promising factors for the objective and NOx emission, smoke density and BTE are considered as response variables. Tests were conducted as per Taguchi’s L9 orthogonal array and the most influencing factor for each response variable and also the significance of each factor on the same was found out through analysis of variance (ANOVA). Response graph was drawn for each response variable and from the results of response graph and ANOVA the optimum combination of the factor levels in achieving the objective was obtained and the same was confirmed experimentally. 相似文献
225.
226.
Chris X. Rao Edwin P Maurer 《Journal of the American Water Resources Association》1996,32(6):1139-1146
ABSTRACT: A simplified approach for modeling transmission losses in a stream is presented. A theory relating seepage from a channel with the depth of flow is simplified to a one-parameter relationship. A power relationship is then utilized for the stage-discharge relationship, which is coupled with the seepage relationship. This combined equation is integrated over the channel reach to arrive at a general model for seepage loss through the reach, with one parameter needing calibration. An example is provided showing the development of the relationship and the calibration technique for the parameter. The results are shown, emphasizing the use of the model for simulation of channel transmission losses at low and moderate flow conditions. 相似文献
227.
ModelingadsorptionofphosphatebysoilswhilethesolutionconcentrationdecreasedwithsorptionSuiHongjianResearchCenterofEnvironment... 相似文献
228.
229.
230.