全文获取类型
收费全文 | 742篇 |
免费 | 23篇 |
国内免费 | 18篇 |
专业分类
安全科学 | 33篇 |
废物处理 | 23篇 |
环保管理 | 136篇 |
综合类 | 112篇 |
基础理论 | 183篇 |
环境理论 | 2篇 |
污染及防治 | 179篇 |
评价与监测 | 85篇 |
社会与环境 | 24篇 |
灾害及防治 | 6篇 |
出版年
2023年 | 6篇 |
2022年 | 7篇 |
2021年 | 8篇 |
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 15篇 |
2017年 | 14篇 |
2016年 | 24篇 |
2015年 | 18篇 |
2014年 | 14篇 |
2013年 | 60篇 |
2012年 | 41篇 |
2011年 | 56篇 |
2010年 | 37篇 |
2009年 | 39篇 |
2008年 | 51篇 |
2007年 | 61篇 |
2006年 | 51篇 |
2005年 | 41篇 |
2004年 | 41篇 |
2003年 | 35篇 |
2002年 | 28篇 |
2001年 | 20篇 |
2000年 | 9篇 |
1999年 | 10篇 |
1998年 | 13篇 |
1997年 | 5篇 |
1996年 | 14篇 |
1995年 | 8篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 6篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有783条查询结果,搜索用时 625 毫秒
31.
Remobilisation of contaminant metals from sediments can occur by chemical, biological or physical changes. This in turn can lead to contaminant fluxes to the porewaters and ultimately the water column. The aim of the research presented here is to document post-depositional controls on metal mobility and fluxes in a heavily metal-contaminated estuary. This will allow for an improved understanding of the impact of contaminated sediments on water quality from both a short-term and long-term perspective. Dulas Bay is situated on the east coast of Anglesey, North Wales, and receives polluted waters from Parys Mountain. Metals within Dulas Bay sediments show surface enrichment and variations in mineralogical form. Diagenesis clearly plays a role in post-depositional behaviour of the metals, forming sulphides and potentially carbonates. The presence of a dominant exchangeable/carbonate fraction, and elevated porewater metals, in this sulphidic system is significant and could indicate the presence of freshwater diagenesis, or, reflect the high levels of metals in the sediment. 相似文献
32.
33.
Chris Pratt Adrian S. Walcroft Julie Deslippe Kevin R. Tate 《Waste management (New York, N.Y.)》2013,33(2):412-419
Landfills that generate too little biogas for economic energy recovery can potentially offset methane (CH4) emissions through biological oxidation by methanotrophic bacteria in cover soils. This study reports on the CH4 oxidation efficiency of a 10-year old landfill cap comprising a volcanic pumice soil. Surface CH4 and CO2 fluxes were measured using field chambers during three sampling intervals over winter and summer. Methane fluxes were temporally and spatially variable (?0.36 to 3044 mg CH4 m?2 h?1); but were at least 15 times lower than typical literature CH4 fluxes reported for older landfills in 45 of the 46 chambers tested. Exposure of soil from this landfill cover to variable CH4 fluxes in laboratory microcosms revealed a very strong correlation between CH4 oxidation efficiency and CH4/CO2 ratios, confirming the utility of this relationship for approximating CH4 oxidation efficiency. CH4/CO2 ratios were applied to gas concentrations from the surface flux chambers and indicated a mean CH4 oxidation efficiency of 72%. To examine CH4 oxidation with soil depth, we collected 10 soil depth profiles at random locations across the landfill. Seven profiles exhibited CH4 removal rates of 70–100% at depths <60 cm, supporting the high oxidation rates observed in the chambers. Based on a conservative 70% CH4 oxidation efficiency occurring at the site, this cover soil is clearly offsetting far greater CH4 quantities than the 10% default value currently adopted by the IPCC. 相似文献
34.
35.
36.
The catalytic effects of copper and iron compounds were examined for their behavior in promoting formation of chlorine (Cl2), the major chlorinating agent of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), in an environment simulating that of municipal waste fly ash. Formation of Cl2 occurred as a result of a metal-catalyzed reaction of HCl with O2. Catalytic activity was greatest at a temperature of approximately 400 °C, supporting a theory of de novo synthesis of PCDDs and PCDFs on fly ash particles downstream of waste combustion. 相似文献
37.
Sedimentary Pigments and Organic Matter in Relation to Benthic Fauna in the Tan-Shui Estuary, Taiwan
The benthic ecological structure of the Tan-Shui estuary, Taiwan is changed due to long term effects of dumping of urban wastewater and of engineering actions. to monitor these changes, we sampled and analyzed benthos and sediment from 12 stations on the estuary.
The composition of the dominant species of benthos varied seasonally, with molluscan and crustacean species having greater numbers and higher frequencies of occurrence than other species. the dominant taxa during winter were Nassarius sp. and Maldanidae at two stations. Analysis using Simpson's index and Shannon's index showed the benthic community varied more in coastal areas than in offshore areas.
Physicochemical analysis showed that most of the Tan-Shui estuary consisted of sandy sediment. the variations in concentrations of organic carbon and total nitrogen at each station were small. Although the concentrations of chlorophyll-a and carotenoid at all stations were generally low, the two stations had the highest concentrations, and we concluded that the concentration of pigments in these sediments was related to the abundance of benthos. the community structure of the benthos reflected the characteristics of the sediments, and benthic species exhibited selection of and adaptation to specific sedimentary environments. 相似文献
The composition of the dominant species of benthos varied seasonally, with molluscan and crustacean species having greater numbers and higher frequencies of occurrence than other species. the dominant taxa during winter were Nassarius sp. and Maldanidae at two stations. Analysis using Simpson's index and Shannon's index showed the benthic community varied more in coastal areas than in offshore areas.
Physicochemical analysis showed that most of the Tan-Shui estuary consisted of sandy sediment. the variations in concentrations of organic carbon and total nitrogen at each station were small. Although the concentrations of chlorophyll-a and carotenoid at all stations were generally low, the two stations had the highest concentrations, and we concluded that the concentration of pigments in these sediments was related to the abundance of benthos. the community structure of the benthos reflected the characteristics of the sediments, and benthic species exhibited selection of and adaptation to specific sedimentary environments. 相似文献
38.
39.
Wahidul K. Biswas John Graham Kevin Kelly Michele B. John 《Journal of Cleaner Production》2010,18(14):1386-1392
This paper compares the life cycle global warming potential of three of Australia’s important agricultural production activities – the production of wheat, meat and wool in grazed subterranean clover (sub-clover) dominant pasture and mixed pasture (perennial ryegrass/phalaris/sub-clover/grass and cape weed) systems. Two major stages are presented in this life cycle assessment (LCA) analysis: pre-farm, and on-farm. The pre-farm stage includes greenhouse gas (GHG) emissions from agricultural machinery, fertilizer, and pesticide production and the emissions from the transportation of these inputs to paddock. The on-farm stage includes GHG emissions due to diesel use in on-farm transport and processing (e.g. seeding, spraying, harvesting, topdressing, sheep shearing), and non-CO2 (nitrous oxide (N2O), and methane (CH4)) emissions from pastures and crop grazing of lambs.The functional unit of this life cycle analysis is the GHG emissions (carbon dioxide equivalents – CO2 -e) from 1 kg of wheat, sheep meat and wool produced from sub-clover, wheat and mixed pasture plots. The GHG emissions (e.g. CO2, N2O and CH4 emission) from the production, transportation and use of inputs (e.g. fertilizer, pesticide, farm machinery operation) during pre-farm and on-farm stages are also included. The life cycle GHG emissions of 1 kg of wool is significantly higher than that of wheat and sheep meat. The LCA analysis identified that the on-farm stage contributed the most significant portion of total GHG emissions from the production of wheat, sheep meat and wool. This LCA analysis also identified that CH4 emissions from enteric methane production and from the decomposition of manure accounted for a significant portion of the total emissions from sub-clover and mixed pasture production, whilst N2O emissions from the soil have been found to be the major source of GHG emissions from wheat production. 相似文献
40.
Shouliang Huo Jingtian Zhang Kevin M. Yeager Beidou Xi Yanwen Qin Zhuoshi He Fengchang Wu 《环境科学学报(英文版)》2023,31(5):1-11
The technique of DGT (diffusive gradients in thin films) using three diffusive gel thicknesses was applied to estimate the mobility and bioavailability of heavy metals in sediments and porewater of Lake Taihu, China. The DGT results showed significantly positive correlations between Co, Pb, Cd and Mn, and Ni and Fe concentrations in porewater. Cu and Zn showed a significantly negative correlation with Mn, due to Cu combination with carbonates and Zn derived from agricultural pollution, respectively. The rank order of average concentrations of Co, Ni and Cd at each station was DGT1.92 > DGT0.78 > DGT0.39, suggesting stronger resupply from sediments to porewater when using thicker diffusive gels. Comparing centrifugation and DGT measurements, Co, Ni and Cd are highly labile; Mn and Fe are moderately labile; and Cu, Zn and Pb are slightly labile. The variations of AVS concentrations in sediment cores indicate that metal sulfides in deeper layers are easily diffused into surface sediments. 相似文献