全文获取类型
收费全文 | 4157篇 |
免费 | 209篇 |
国内免费 | 1588篇 |
专业分类
安全科学 | 285篇 |
废物处理 | 292篇 |
环保管理 | 288篇 |
综合类 | 2390篇 |
基础理论 | 692篇 |
环境理论 | 1篇 |
污染及防治 | 1541篇 |
评价与监测 | 142篇 |
社会与环境 | 128篇 |
灾害及防治 | 195篇 |
出版年
2024年 | 1篇 |
2023年 | 69篇 |
2022年 | 186篇 |
2021年 | 166篇 |
2020年 | 133篇 |
2019年 | 110篇 |
2018年 | 147篇 |
2017年 | 189篇 |
2016年 | 184篇 |
2015年 | 234篇 |
2014年 | 276篇 |
2013年 | 449篇 |
2012年 | 353篇 |
2011年 | 367篇 |
2010年 | 287篇 |
2009年 | 288篇 |
2008年 | 313篇 |
2007年 | 257篇 |
2006年 | 228篇 |
2005年 | 176篇 |
2004年 | 117篇 |
2003年 | 145篇 |
2002年 | 163篇 |
2001年 | 100篇 |
2000年 | 126篇 |
1999年 | 146篇 |
1998年 | 121篇 |
1997年 | 110篇 |
1996年 | 103篇 |
1995年 | 112篇 |
1994年 | 82篇 |
1993年 | 68篇 |
1992年 | 50篇 |
1991年 | 33篇 |
1990年 | 14篇 |
1989年 | 6篇 |
1988年 | 15篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 9篇 |
1981年 | 3篇 |
排序方式: 共有5954条查询结果,搜索用时 47 毫秒
721.
722.
分析了年产15万t啤酒的生产废水情况,介绍了采用IC厌氧反应器-一体化氧化沟处理该生产废水(7 200 m3/d)的工艺路线和主要设计参数,讨论了废水处理系统的运行情况.其中IC厌氧反应器的HRT为8 h,运行温度为35~37 ℃;一体化氧化沟包括氧化沟段和沉淀池段,总尺寸为40 m×24 m×6 m.IC厌氧反应器COD容积负荷在7.78 kg/(m3·d)时,COD去除率为84%左右.整套废水处理系统的COD总去除率为98%左右,出水COD小于80 mg/L.厌氧所产生的沼气可用于废水的升温. 相似文献
723.
The distribution of trace metals Zn, Ni, Mn, Fe, Cu, Pb, Cd and Cr between suspended particulate matter (SPM) and water in the Conwy estuary, North Wales, has been studied in three surveys in 1998. Dissolved Cu and Mn showed some monthly variations. Most of the dissolved trace metals displayed a negative association with salinity, indicating rivers as a major source of inputs for them. Particulate Zn, Mn and Fe showed a decreasing concentration seaward, whilst the levels of Ni, Cu, Cr and Pb increased with salinity. SPM concentration was the most important variable significantly related to trace metal concentrations in SPM, with an inverse relationship between the two parameters. This was explained by the relative enrichment of trace metals in fine particles at low SPM concentrations and relative depletion of trace metals in coarse particles at high SPM concentrations. Particulate Zn, Mn and Pb were dominated by the fraction available to acetic acid (non-detrital), whilst particulate Ni, Fe and Cr were dominated by the fraction available to nitric acid (detrital). The partition coefficient of trace metals between SPM and water declined with increasing SPM concentration, consistent with the so-called "particle concentration effect". Such a phenomenon may be explained by the presence of fine particles (including colloids) enriched with trace metals at low SPM concentrations, and the salinity-induced desorption. 相似文献
724.
725.
726.
不同粒度飞灰中16种微量元素的含量分布 总被引:7,自引:0,他引:7
研究了不同粒级的燃煤飞灰中的Ba、Be、Cd、Cr、Cu、Hg、Li、Mn、Ni、Pb、Sr、Ti、V、Zn、Zr元素的含量分布,煤中元素的含量比及富集因子。 相似文献
727.
728.
729.
730.
The sorption and desorption of Cu and Cd by two species of brown macroalgae and five species of microalgae were studied. The two brown macroalgae, Laminaria japonica and Sargassum kjellmanianum, were found to have high capacities at pHs between 4.0 and 5.0 while for microalgae, optimum pH lay at 6.7. The presence of other cations in solution was found to reduce the sorption of the target cation, suggesting a competition for sorption sites on organisms. Sorption isotherms obeyed the Freundlich equation, suggesting involvement of a multiplicity of mechanisms and sorption sites. For the microalgae tested, Spirulina platensis had the highest capacity for Cd, followed by Nannochloropsis oculata, Phaeodactylum tricornutum, Platymonas cordifolia and Chaetoceros minutissimus. The reversibility of metal sorption by macroalgae was examined and the results show that both HCl and EDTA solutions were very effective in desorbing sorbed metal ions from macroalgae, with up to 99.5% of metals being recovered. The regenerated biomass showed undiminished sorption performance for the two metals studied, suggesting the potential of such material for use in water and wastewater treatment. 相似文献