全文获取类型
收费全文 | 757篇 |
免费 | 78篇 |
国内免费 | 356篇 |
专业分类
安全科学 | 43篇 |
废物处理 | 31篇 |
环保管理 | 69篇 |
综合类 | 659篇 |
基础理论 | 152篇 |
环境理论 | 1篇 |
污染及防治 | 124篇 |
评价与监测 | 72篇 |
社会与环境 | 36篇 |
灾害及防治 | 4篇 |
出版年
2024年 | 4篇 |
2023年 | 28篇 |
2022年 | 47篇 |
2021年 | 50篇 |
2020年 | 33篇 |
2019年 | 52篇 |
2018年 | 49篇 |
2017年 | 52篇 |
2016年 | 44篇 |
2015年 | 62篇 |
2014年 | 47篇 |
2013年 | 80篇 |
2012年 | 61篇 |
2011年 | 67篇 |
2010年 | 35篇 |
2009年 | 38篇 |
2008年 | 55篇 |
2007年 | 58篇 |
2006年 | 51篇 |
2005年 | 43篇 |
2004年 | 32篇 |
2003年 | 28篇 |
2002年 | 21篇 |
2001年 | 16篇 |
2000年 | 30篇 |
1999年 | 16篇 |
1998年 | 21篇 |
1997年 | 12篇 |
1996年 | 21篇 |
1995年 | 7篇 |
1994年 | 8篇 |
1993年 | 9篇 |
1992年 | 1篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1985年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有1191条查询结果,搜索用时 639 毫秒
531.
Sana Ullah Xuejun Guo Xiaoyan Luo Xiangyuan Zhang Siwen Leng Na Ma Palwasha Faiz 《Frontiers of Environmental Science & Engineering》2020,14(5):89
532.
FRANCISCO GALLARDO-LARA MARIANO AZCÓN ALFREDO POLO 《Journal of environmental science and health. Part. B》2013,48(7):1187-1201
Little is known about the effects of applying composted urban wastes on the phytoavailability and distribution of iron (Fe) and manganese (Mn) among chemical fractions in soil. In order to study this concern several experiments in pots containing calcareous soil were carried out. The received treatments by adding separately two rates (20 and 80 Mg ha?1) of municipal solid waste (MSW) compost and/or municipal solid waste and sewage sludge (MSW-SS) co-compost. The cropping sequence was a lettuce crop followed by a barley crop. It was observed that treatments amended with composted urban wastes tended to promote slight increases in lettuce yield compared to the control. The highest Fe levels in lettuce were found when higher rates of MSW-SS co-compost were applied; these values were significant compared to those obtained in the other treatments. In all cases, the application of organic materials increased the concentration and uptake of Mn in lettuce compared to the control; however, these increases were significant only when higher rates of MSW compost were applied. The organic amendments had beneficial delayed effects on barley yields, showing, in most cases, significant increases compared to the control. In this context, treatments with MSW compost were found to be more effective than the equivalent treatments amended with MSW-SS co-compost. Compared to the control, composted urban wastes increased Fe concentration in straw and rachis, and decreased Fe concentration in barley grain. Similarly, a decreased concentration of Mn in the dry matter of barley crop grown in soils treated with composted urban wastes was observed. 相似文献
533.
Stefan Tsakovski Marek Tobiszewski ?aneta Polkowska 《Environmental pollution (Barking, Essex : 1987)》2010,158(1):84-91
This study deals with the assessment of roof runoff waters from the region of Gdansk collected during the winter season (2007/2008). The chemical analysis includes 16 chemical variables: major ions, PAHs and PCBs measured at 3 sampling sites for 6-14 rain events. Although the data set is of limited volume the statistical data treatment using self-organizing maps (SOM) reveals the main factors controlling roof runoff water quality even for a data set with small dimension. This effort for explanation of the identified factors by the possible emission sources of the urban environment and air-particulate formation seems to be very reliable. Additionally to the roof runoff water quality factors the rain events patterns are found: “background” group of events and groups formally named “PAHs”, “PCBs” and “air-borne particles” - dominated events. The SOM classification results give an opportunity to uncover the role of roof “impact” on the runoff waters.Rain runoff water quality is described by four latent factors and the “roof” impact is uncovered. 相似文献
534.
535.
Joachim von Schéele 《International Journal of Green Energy》2013,10(2):139-148
There is a strong political will to decrease CO2 emissions. Although the steel industry only accounts for some 5% of worldwide CO2 emissions (which totalled 1,200 million tonnes per annum in the late 1990s), it will be strongly affected by this. The EU, for example, is putting up strong economic incentives for reductions. This is taking place at a time when demand for steel products is greater than ever. To radically change existing processes and production routes to decrease the CO2 emissions would be extremely expensive, even if it were possible. Nevertheless, many of the solutions which have been discussed seem to go in this direction. The other alternative discussed seems to be the creation of process solutions and alterations that lead to a focusing of CO2 streams, i.e., much higher CO2 concentrations in flue gases than today, for entrapment of the CO2 so that it is not discharged into the atmosphere. These solutions are feasible, but expensive. However, there exists today a number of solutions and technologies which, if fully implemented, could substantially decrease CO2 emissions without seriously altering current methods of operation; they are short-term viable solutions. The present paper reviews and discusses such technologies, throughout the steel production paths. If these solutions are fully implemented, the combined impact on CO2 emissions from the steel industry worldwide is estimated to be a reduction of 100–150 million tonnes of CO2 per annum, i.e., current emissions can be reduced by some 8–10% within a relatively short time span. 相似文献
536.
硝基芳香化合物(NACs)是细颗粒物中含氮化合物的重要组成部分,研究其在大气中的污染特征和季节变化,有助于表征大气细颗粒物中含氮有机化合物特性,并为城市氮氧化物削减提供科学支撑.采集并分析了上海城区2018年3月~2019年2月大气PM2.5样品,采用超高效液相色谱-轨道阱质谱(UPLC-Orbitrap MS)在PM2.5样品中定性检测到了2 439~3 695个有机物,内标法定量了9种NACs,春季ρ(NACs)范围为3.12~16.8 ng·m-3,平均值为9.31 ng·m-3;夏季ρ(NACs)范围为1.05~9.70 ng·m-3,平均值4.16 ng·m-3;秋季ρ(NACs)范围为2.87~36.27 ng·m-3,平均值9.84 ng·m-3,冬季ρ(NACs)范围为4.83~56.23 ng·m-3,平均值为22.37 ng·m-3. 9种硝基芳香化... 相似文献
537.
本研究改进了传统有机样品前处理步骤,将大气细颗粒物样品直接装填于TD管并与气相色谱联用的自动化热脱附装置,建立的新型热脱附(thermo desorption,TD)与气相色谱/质谱(GC/MS)联用方法,对72种非极性有机物(non-polar organic compounds,NPOCs),包括34种多环芳烃(polylicycle aromatic hydrocarbon,PAHs)、1种苯并噻吩、27种(C_(10)~C_(34))烷烃(alkanes)、5种霍烷(hopanes)和5种甾烷(steranes)化合物进行定量分析.优化了承载样品装填方式、热脱附条件和进样模式等参数.结果表明,热脱附-气相色谱/质谱方法对多环芳烃、正构烷烃、霍烷和甾烷的检出限分别为0.01~1.0、0.1~8.0和0.50~2.0 ng·m~(-3),标定曲线线性相关系数在0.9以上.热脱附效率分别为:多环芳烃95%~100%、正构烷烃81%~100%、霍烷和甾烷83.1%~100%.与传统溶剂超声萃取的方法差异性比较结果表明,两种方法分析结果的偏差基本小于30%,在可接受范围内.对临安和上海PM_(2.5)中的痕量NPOCs的定量分析表明,采样期间两地大气PM_(2.5)中NPOCs以烷烃为主,其次为PAHs.特征比值法分析结果表明,大气细颗粒物污染主要来自化石燃料燃烧和煤炭燃烧. 相似文献
538.
The fertilizing potential of Fe-enriched biosolids has been attributed to Fe associations with humic substances contained therein. In this study, alkaline and near-neutral aqueous extractions of humic substances from an Fe-enriched biosolid were followed by gel chromatographic fractionation and characterization (CHNS elemental analysis; UV/visible and FTIR spectroscopy; FAAS analysis). The alkaline bulk humic extract had a strong fulvic character and Fe was predominantly associated with the higher molecular weight (50 000 Da) molecules, possibly including organic-coated Fe oxides from which Fe may be released more slowly. Under both near-neutral and alkaline conditions, associations with lower molecular weight humic molecules were also observed, indicative of the presence of Fe in more readily available forms. Thus the biosolid appears to have good short- and long-term fertilizing potential, particularly for alkaline, Fe-deficient soils. 相似文献
539.
Depth profiles of the specific activities of (14)C and carbon isotopic compositions (Delta(14)C, delta(13)C) in soil organic matter and soil CO(2) in a Japanese larch forest were determined. For investigating the transport of CO(2) in soil, specific activities of (14)C, Delta(14)C and delta(13)C in the organic layer, and atmospheric CO(2) in the same forest area were also determined. The specific activity of (14)C and Delta(14)C in the soil organic matter decreased with the increase in depth of 0-60cm, while that of soil CO(2) did not vary greatly at a soil depth of 13-73cm and was more prevalent than that of atmospheric CO(2). Peaks of specific activities of (14)C appeared at the depth of 0-4cm and Delta(14)C values were positive in the depth range from 0 to 15cm. These results suggest that the present soil at a depth of 0-4cm had been produced from the mid-1950s up until 1963, and the bomb C had reached the depth of 15cm in the objective soil area. The delta(13)C in the soil organic matter increased at the depth of 0-55cm, while that of soil CO(2) collected on 8 November 2004 decreased rapidly at the depth of 0-13cm and only slightly at the depth of 53-73cm. By combining the Delta(14)C and delta(13)C of the respective components and using the Keeling plot approach it was made clear that the entering of atmospheric CO(2) showed a large contribution to soil CO(2) at the depth of 0-13cm and a negligible contribution at the depth of 53-73cm for soil air collected on 8 November 2004. Respiration of live roots was presumed to be the main source of soil CO(2) at the depth of 53-73cm on 8 November 2004. 相似文献
540.
Current knowledge of sorption processes in tropical soils is reviewed. Landscapes throughout the tropics are dominated by oxisols which occupy extensive areas of potentially highly productive soils. These soils are dominated by low-activity sesquioxide minerals and clays that have variable charge surfaces. The limited information on tropical soils available suggests that the composition of the ambient soil solution can influence sorption through changes in particle surface-charge density. Thus the observed decrease in sorption in the presence of divalent index cations may be related to the effect of ionic charge on the double-layer thickness which is manifested through a change in surface-charge characteristics. However, much work needs to be done to differentiate the effect of cation charge on surface-charge density from the competitive effect between the index cation and heavy-metal ions for the sorption sites. The effects of inorganic and organic ligands on adsorption of Cd by variable charge surfaces are also reviewed. 相似文献