全文获取类型
收费全文 | 203篇 |
免费 | 23篇 |
国内免费 | 23篇 |
专业分类
安全科学 | 2篇 |
废物处理 | 6篇 |
环保管理 | 21篇 |
综合类 | 103篇 |
基础理论 | 27篇 |
污染及防治 | 41篇 |
评价与监测 | 26篇 |
社会与环境 | 9篇 |
灾害及防治 | 14篇 |
出版年
2023年 | 5篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 5篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 10篇 |
2014年 | 11篇 |
2013年 | 10篇 |
2012年 | 11篇 |
2011年 | 12篇 |
2010年 | 11篇 |
2009年 | 15篇 |
2008年 | 8篇 |
2007年 | 15篇 |
2006年 | 14篇 |
2005年 | 5篇 |
2004年 | 7篇 |
2003年 | 15篇 |
2002年 | 7篇 |
2001年 | 7篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 10篇 |
1997年 | 9篇 |
1996年 | 2篇 |
1995年 | 8篇 |
1994年 | 10篇 |
1993年 | 1篇 |
1992年 | 6篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有249条查询结果,搜索用时 31 毫秒
1.
Disha Sharma 《Chemistry and Ecology》2018,34(5):470-481
This is the first study in the Delhi region that assesses the critical load capacity of soil systems with respect to the atmospheric deposition and air quality, from July to October in 2012. Trend analysis of NO2 and SO2 in Delhi, using the Central Pollution Control Board (CPCB) data, showed interesting patterns matching with the trends in vehicular load in the city. This was followed by the calculation of the critical load of atmospheric acidity for sulphur and nitrogen in order to check the vulnerability of the soil systems in Delhi. Here, the steady state mass balance approach was majorly applied and the study conducted in the Agra region was taken as reference. The calculated values of critical loads of sulphur (225–275?eq/ha/yr) and nitrogen (298–303?eq/ha/yr), for the soil system in Delhi, were calculated with respect to three plant species, namely Anjan grass, Hibiscus and Black siris. The present loads of sulphur (PL(S)?=?26.40?eq/ha/yr) and nitrogen (PL(N)?=?36.51?eq/ha/yr) were found to be much lower than their respective critical loads. From the results, it can be concluded that the present loads of atmospheric acidic deposition in Delhi region do not pose any danger of acidification of soil system because it is countered by buffering capacity of soil generated dust. However, considering the pace at which the city is growing, it is likely that in coming decades, the present load will increase and thus the values evaluated in this study are likely to serve as an important reference for future assessment of the pollution scenario in the city. 相似文献
2.
3.
在泸州市2016—2020年大气降水监测数据的基础上,借助聚类分析、多元方差分析等统计分析手段,对原有降水监测点位进行优化研究,并验证优化结果。在遵循《酸沉降监测技术规范》(HJ/T 165—2004)点位布设要求的前提下,建立了降水监测点位评价体系,从原有7个降水监测点位中优化筛选出3个。优化后的点位对监测结果的影响显著性均>0.05,表明优化前后全市降水数据无显著性差异,该优化方案不会影响区域整体代表性。 相似文献
4.
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
5.
6.
The pH of machine-made snow and its effect on an acid-sensitive watershed in Vermont were studied. Spring runoff from snowmaking was found to be less acidic and to contain less dissolved inorganic aluminum. Dissolved inorganic aluminum has been associated with damage to aquatic life. The extensive use of machine-made snow by the ski industry in most of the northeast region of the US may be beneficial to aquatic life. 相似文献
7.
《Journal of environmental science and health. Part. B》2013,48(4):501-509
A study was conducted to investigate the suitability of phosphate recovery from greenhouse wastewaters by using precipitation/crystallization process. More than 90% of the phosphate could be removed from the greenhouse wastewater. Various calcium phosphate salts were obtained in the process; hydroxyapatite [Ca5(PO4)3OH] could be the main product from the precipitates. Phosphate removal was affected by the presence of magnesium ion in wastewaters. An increase of magnesium concentrations in wastewaters decreased phosphate removal rates. The chemical contents of precipitates in terms of calcium, magnesium and phosphate were affected by calcium to magnesium molar ratio. Higher calcium contents were obtained at wastewaters with high calcium to magnesium molar ratio. An addition of magnesium did not affect the potassium contents in the precipitates. K‐struvite, MgKPO4·6H2O, was not the major product in the precipitate, even with addition of a large quantity of magnesium. 相似文献
8.
《Journal of environmental science and health. Part. B》2013,48(2):363-374
Phosphorus recovery from greenhouse wastewater, using precipitation-crystallization, was conducted under three levels of calcium concentration, 304 mg/L (7.6 mmol/L), 384 mg/L (9.6 mmol/L), and 480 mg/L (12 mmol/L), and also with additions of ammonium and magnesium into the wastewater. Jar test results confirmed high phosphate removal, with more than 90% of the removal achieved with a pH as low as 7.7. Under the low calcium concentration, ammonium addition affected the chemical reactions at pH lower than 8.0, where struvite was produced; when the pH was raised to 8.8, other calcium compounds dominated the precipitation. Under the medium calcium concentration, ammonium and magnesium addition helped struvite precipitation in the low pH range. Hydroxyapatite (HAP) was the main product. Under the high calcium concentration, ammonium addition showed no effects on the precipitation. 相似文献
9.
The activity concentrations of Beryllium-7 (7Be), a naturally occurring radioisotope produced in the atmosphere, were measured in leaves of birch-trees, above-ground parts of grass, soil and rainwater in the mountain massive Kralicky Sneznik (the northeast of the Czech Republic, altitude about 750 m) in the years of 2005, 2006 and 2007. Dried and ground samples of the plants and soils, and water samples from wet deposition were used to determine the 7Be content using a semiconductor gamma spectrometer. The 7Be values ranged from 147.0 to 279.6 Bq kg−1, from 48.7 to 740.8 Bq kg−1, from 2.1 to 8.7 Bq kg−1, and from 0.6 to 1.9 Bq kg−1 in birch-tree leaves, grass samples, soils, and rainwater, respectively. Insignificant inter-annual variations but significant increase in the 7Be activity concentrations during the spring and summer months were observed in birch-tree leaves and grass samples. The seasonal variation of the 7Be concentrations in grass samples correlated (R2 = 0.4663 and 0.6489) with precipitation. No similar correlation was found for 7Be in birch-tree leaves. Beryllium-7 content in birch-tree leaves and in aerial parts of grass was mainly caused by direct transport of 7Be from wet deposition into aerial parts of the observed plants. 相似文献
10.
海南五指山和福建武夷山降水离子组成及来源 总被引:2,自引:0,他引:2
分析海南五指山及福建武夷山大气背景点2008年1月—2009年12月的降水pH及离子组成,并探讨离子来源.结果表明:海南五指山监测点降水年均pH约为5.64,呈中性;武夷山监测点降水的年均pH约为5.30,呈弱酸性.2个监测点降水中的SO42-、NO3-和NH4+的浓度和占总离子浓度的59%左右,表现出与城市相似的组成特征,表明这2个监测点的降水已经受到人类活动的影响.降水酸度除受SO42-和NO3-的影响外,还受到NH4+、Ca2+和Mg2+等碱性物质的中和作用.相对酸度和中和因子的计算表明,五指山和武夷山监测点降水酸度分别有85%和76%被碱性物质NH4+和Ca2+中和.富集因子计算及来源定量分析表明,这2个监测点已受到人为源的影响,人为源的贡献大于海洋源及地壳源.武夷山监测点88%的Ca2+和56%的K+均来自人为源,主要是受人为污染物长距离传输及生物质燃烧的影响. 相似文献