全文获取类型
收费全文 | 1208篇 |
免费 | 188篇 |
国内免费 | 878篇 |
专业分类
安全科学 | 97篇 |
废物处理 | 192篇 |
环保管理 | 111篇 |
综合类 | 1413篇 |
基础理论 | 138篇 |
污染及防治 | 281篇 |
评价与监测 | 29篇 |
社会与环境 | 8篇 |
灾害及防治 | 5篇 |
出版年
2024年 | 4篇 |
2023年 | 20篇 |
2022年 | 57篇 |
2021年 | 57篇 |
2020年 | 66篇 |
2019年 | 91篇 |
2018年 | 77篇 |
2017年 | 72篇 |
2016年 | 100篇 |
2015年 | 122篇 |
2014年 | 112篇 |
2013年 | 110篇 |
2012年 | 148篇 |
2011年 | 136篇 |
2010年 | 109篇 |
2009年 | 114篇 |
2008年 | 81篇 |
2007年 | 129篇 |
2006年 | 143篇 |
2005年 | 110篇 |
2004年 | 97篇 |
2003年 | 74篇 |
2002年 | 44篇 |
2001年 | 42篇 |
2000年 | 36篇 |
1999年 | 22篇 |
1998年 | 15篇 |
1997年 | 23篇 |
1996年 | 15篇 |
1995年 | 13篇 |
1994年 | 9篇 |
1993年 | 7篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1984年 | 2篇 |
1974年 | 1篇 |
1973年 | 2篇 |
排序方式: 共有2274条查询结果,搜索用时 46 毫秒
41.
用硫酸渣制备铁基颜料铁黄 总被引:6,自引:0,他引:6
以硫酸渣为原料,用黄铁矿粉作还原剂,采用湿式空气氧化法制备铁基颜料铁黄。试验得出的适宜工艺条件为:Fe^2 浓度0.25—0.40mol/L,氧化温度70℃,用氢氧化钠或氨水调节反应液的pH,氧化过程溶液的pH控制在3—4。依照该工艺制得的铁基颜料铁黄,其各项指标符合HG/T2249—91标准。 相似文献
42.
Occurence and Distribution of Polycyclic Aromatic Hydrocarbons in Ankara Precipitation 总被引:1,自引:0,他引:1
Urban atmospheric environment contains many trace organic pollutants that are related to the incomplete fuel combustion in domestic heating, industrial plants and automobile traffic. Removal of these pollutants from the atmosphere takes place through wet and dry deposition as well as chemical transformations. In this study, concentrations of polycyclic aromatic hydrocarbons (PAHs) in wet deposition samples were determined at an urban site of Turkey. Wet and dry deposition samples were collected using Andersen Rain Sampler. The sampler was modified accordingly for the collection of organic pollutants. Collected samples were preconcentrated by using solid phase extraction (SPE) disks and consecutively analyzed by Gas Chromatography-Mass Spectrometry (GC-MS). Among the 13 compounds quantified in this study, anthracene, fluoranthene, and pyrene were found more frequently and at elevated concentrations (202, 271 and 260 ng L-1 mean concentrations, respectively).Concentrations of PAHs were found to be high in winter period. 相似文献
43.
Jon E. Schoonover Karl W. J. Williard 《Journal of the American Water Resources Association》2003,39(2):347-354
ABSTRACT: Ground water contamination by excess nitrate leaching in row‐crop fields is an important issue in intensive agricultural areas of the United States and abroad. Giant cane and forest riparian buffer zones were monitored to determine each cover type's ability to reduce ground water nitrate concentrations. Ground water was sampled at varying distances from the field edge to determine an effective width for maximum nitrate attenuation. Ground water samples were analyzed for nitrate concentrations as well as chloride concentrations, which were used as a conservative ion to assess dilution or concentration effects within the riparian zone. Significant nitrate reductions occurred in both the cane and the forest riparian buffer zones within the first 3.3 m, a relatively narrow width. In this first 3.3 m, the cane and forest buffer reduced ground water nitrate levels by 90 percent and 61 percent, respectively. Approximately 40 percent of the observed 99 percent nitrate reduction over the 10 m cane buffer could be attributed to dilution by upwelling ground water. Neither ground water dilution nor concentration was observed in the forest buffer. The ground water nitrate attenuation capabilities of the cane and forest riparian zones were not statistically different. During the spring, both plant assimilation and denitrification were probably important nitrate loss mechanisms, while in the summer nitrate was more likely lost via denitrification since the water table dropped below the rooting zone. 相似文献
44.
45.
SCR反应塔入口段烟气速度场的数值模拟 总被引:2,自引:1,他引:2
使用商业计算软件CFX5.7.1,采用标准k-ε湍流模型,模拟了SCR脱硝反应塔入口段烟气速度场,并分析比较了导流板对烟气速度场的影响及均匀SCR反应塔进口处烟气速度场的作用。 相似文献
46.
火电厂石灰石湿法烟气脱硫废水处理方法 总被引:20,自引:1,他引:20
阐述了石灰石湿法烟气脱硫(FGD)废水的水质特征,介绍了国内外普遍应用的化学沉淀去除脱硫废水中重金属、悬浮物等物质的工艺特点及其不足,并着重介绍了最新发展的流化床法、沉淀一微滤法等FCD废水处理新型工艺。 相似文献
47.
48.
49.
50.