全文获取类型
收费全文 | 2539篇 |
免费 | 306篇 |
国内免费 | 1934篇 |
专业分类
安全科学 | 216篇 |
废物处理 | 126篇 |
环保管理 | 295篇 |
综合类 | 2849篇 |
基础理论 | 418篇 |
环境理论 | 1篇 |
污染及防治 | 785篇 |
评价与监测 | 62篇 |
社会与环境 | 25篇 |
灾害及防治 | 2篇 |
出版年
2024年 | 11篇 |
2023年 | 42篇 |
2022年 | 92篇 |
2021年 | 159篇 |
2020年 | 148篇 |
2019年 | 165篇 |
2018年 | 147篇 |
2017年 | 130篇 |
2016年 | 176篇 |
2015年 | 221篇 |
2014年 | 255篇 |
2013年 | 308篇 |
2012年 | 315篇 |
2011年 | 305篇 |
2010年 | 241篇 |
2009年 | 285篇 |
2008年 | 184篇 |
2007年 | 306篇 |
2006年 | 274篇 |
2005年 | 192篇 |
2004年 | 147篇 |
2003年 | 163篇 |
2002年 | 89篇 |
2001年 | 80篇 |
2000年 | 75篇 |
1999年 | 61篇 |
1998年 | 30篇 |
1997年 | 44篇 |
1996年 | 30篇 |
1995年 | 24篇 |
1994年 | 18篇 |
1993年 | 11篇 |
1992年 | 13篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有4779条查询结果,搜索用时 143 毫秒
581.
根据燃油锅炉烟气有害气体成分的特点 ,采用混合液体吸收与气液冲击相结合的方法设计了 1套除尘与脱硫闭路循环净化系统来处理燃油锅炉烟气 ,实践表明 ,该方法能够有效地解决燃油锅炉烟气污染问题 ,使其达标排放。 相似文献
582.
583.
J. S. Gaffney N. A. Marley M. M. Cunningham P. V. Doskey 《Atmospheric environment (Oxford, England : 1994)》1999,33(30):10265
Peroxyacyl nitrates (PANs) were measured using gas chromatography with electron capture detection (GC/ECD) in north central Mexico City during February–March of 1997. Peroxyacetyl nitrate (PAN) was observed to exceed 30 ppb during five days of the study, with peroxypropionyl nitrate (PPN) and peroxybutryl nitrate (PBN) reaching 6 and 1 ppb maximum, respectively. Levels of total PANs typically exceeded 10 ppb during the period of measurement and showed a very strong diurnal variation with PANs maximum during the early afternoon and falling to less than 0.1 ppb during the evening hours. These levels of PANs are the highest reported values in North America (and the world) for an urban center, since levels of approximately 30 ppb were reported during the late 1970s in the Los Angeles area (South Coast Air Basin, Tuazon et al., 1978). Hydrocarbon measurements indicate that the levels of olefins, specifically butenes are significant in Mexico City. A time series taken of source indicator hydrocarbons taken before and during a Mexican National Holiday with reduced automobile traffic clearly show that mobile sources of butenes are as important as liquefied petroleum gas. Observations of 10–40 ppb C methyl-t-butyl ether (MTBE) are consistent with MTBE/gasoline fuel usage as a source of isobutene and formaldehyde. Both these reactive species can lead to increased oxidant and PAN formation. The strong diurnal profiles of PANs are consistent with regional clearing of the Mexico City air basin on a daily basis. Estimates are given using a simple box model calculation for a number of key primary and secondary pollutant emissions from this megacity on an annual basis. These calculations indicate that megacities can be important sources of both primary and secondary pollutants, and that PANs produced in megacity environments are likely to contribute strongly to regional scale ozone and aerosol productions during long range transport. 相似文献
584.
废石粉渣制备混凝剂及其除浊净水效果研究 总被引:3,自引:0,他引:3
利用废石粉渣制备无机混凝剂,并研究所得初产品对硅藻土悬浮液和受污湖水样品进行处理的适宜操作条件以及除浊净水效果,结果表明,利用某些废石粉渣制备的混凝剂有较好效果,但制备工艺有待改善。 相似文献
585.
586.
Gerald Spindler Konrad Müller Hartmut Herrmann 《Environmental science and pollution research international》1999,6(2):89-94
Aerosol filter samples have been collected nearby the industrialised basin of Leipzig in Saxony (Germany) at the research station Melpitz of the Institut für Troposphärenforschung e.V. (IfT). Time series (1992–1998) and a three year comparison (1995–1997) of two different aerosol filter sampling systems, the Sierra-Andersen-PM 10 high volume sampler (daily sample, PM 10 inlet) and the Rupprecht and Patashnik Co. Inc. Model Partisol 2000 (weekly sample, PM 10 and PM 2.5 inlet) are presented and discussed. The comparison of the different sampling systems and strategies yields small differences between the daily and weekly samples for mass and different ions, which may be influenced by sampling duration and flow rates. A general trend of change in aerosol composition was observed: Soot and Sulphate concentrations decreased whereas Nitrate and Ammonium concentrations increased. During summers the mass of coarse particles is higher than in other seasons. One reason could be found in the occurence of longer periods of dry ground surfaces enabling reemission of crustal and biological material. The time series have been integrated in a longer historical aerosol mass trend for Saxony and do show a good agreement. Since 1990 a significant downward trend in gravimetric mass concentration was found. 相似文献
587.
588.
589.
Jiachuang Shao Penghui Shao Mingming Peng Min Li Ziwei Yao Xiuqin Xiong Caiting Qiu Yufan Zheng Liming Yang Xubiao Luo 《Frontiers of Environmental Science & Engineering》2023,17(3):33
590.