全文获取类型
收费全文 | 1463篇 |
免费 | 97篇 |
国内免费 | 343篇 |
专业分类
安全科学 | 87篇 |
废物处理 | 17篇 |
环保管理 | 290篇 |
综合类 | 661篇 |
基础理论 | 207篇 |
污染及防治 | 446篇 |
评价与监测 | 127篇 |
社会与环境 | 55篇 |
灾害及防治 | 13篇 |
出版年
2024年 | 2篇 |
2023年 | 25篇 |
2022年 | 50篇 |
2021年 | 48篇 |
2020年 | 43篇 |
2019年 | 51篇 |
2018年 | 43篇 |
2017年 | 54篇 |
2016年 | 66篇 |
2015年 | 58篇 |
2014年 | 68篇 |
2013年 | 124篇 |
2012年 | 95篇 |
2011年 | 138篇 |
2010年 | 75篇 |
2009年 | 128篇 |
2008年 | 111篇 |
2007年 | 95篇 |
2006年 | 95篇 |
2005年 | 57篇 |
2004年 | 73篇 |
2003年 | 48篇 |
2002年 | 49篇 |
2001年 | 66篇 |
2000年 | 46篇 |
1999年 | 22篇 |
1998年 | 43篇 |
1997年 | 30篇 |
1996年 | 8篇 |
1995年 | 10篇 |
1994年 | 12篇 |
1993年 | 10篇 |
1992年 | 11篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1986年 | 1篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1968年 | 1篇 |
排序方式: 共有1903条查询结果,搜索用时 15 毫秒
101.
Partitioning behaviour of perfluorinated alkyl contaminants between water, sediment and fish in the Orge River (nearby Paris, France) 总被引:3,自引:0,他引:3
This paper reports on the partitioning behaviour of 15 perfluorinated compounds (PFCs), including C4-C10 sulfonates and C5-C14 carboxylic acids, between water, sediment and fish (European chub, Leuciscus cephalus) in the Orge River (nearby Paris). Total PFC levels were 73.0 ± 3.0 ng L−1 in water and 8.4 ± 0.5 ng g−1 in sediment. They were in the range 43.1-4997.2 ng g−1 in fish, in which PFC tissue distribution followed the order plasma > liver > gills > gonads > muscle. Sediment-water distribution coefficients (log Kd) and bioaccumulation factors (log BAF) were in the range 0.8-4.3 and 0.9-6.7, respectively. Both distribution coefficients positively correlated with perfluoroalkyl chain length. Field-based biota-sediment accumulation factors (BSAFs) are also reported, for the first time for PFCs other than perfluorooctane sulfonate. log BSAF ranged between −1.3 and 1.5 and was negatively correlated with the perfluoroalkyl chain length in the case of carboxylic acids. 相似文献
102.
Changes in Streambed Composition in Salmonid Spawning Habitat of the Elwha River during Dam Removal
下载免费PDF全文
![点击此处可从《Journal of the American Water Resources Association》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Roger J. Peters Martin Liermann Michael L. McHenry Paul Bakke George R. Pess 《Journal of the American Water Resources Association》2017,53(4):871-885
One uncertainty associated with large dam removal is the level of downstream sediment deposition and associated short‐term biological effects, particularly on salmonid spawning habitat. Recent studies report downstream sediment deposition following dam removal is influenced by proximity to the source and river transport capacity. The impacts of dam removal sediment releases are difficult to generalize due to the relatively small number of dam removals completed, the variation in release strategies, and the physical nature of systems. Changes to sediment deposition and associated streambed composition in the Elwha River, Washington State, were monitored prior to (2010‐2011) and during (2012‐2014) the simultaneous removal of two large dams (32 and 64 m). Changes in the surface layer substrate composition during dam removal varied by year and channel type. Riffles in floodplain channels downstream of the dams fined and remained sand dominated throughout the study period, and exceeded levels known to be detrimental to incubating salmonids. Mainstem riffles tended to fine to gravel, but appear to be trending toward cobble after the majority of the sediment was released and transported through system. Thus, salmonid spawning habitats in the mainstem appear to have been minimally impacted while those in floodplain channels appear to have been severely impacted during dam removal. 相似文献
103.
A decision framework for possible remediation of contaminated sediments in the River Kymijoki, Finland 总被引:1,自引:1,他引:0
Verta M Kiviranta H Salo S Malve O Korhonen M Verkasalo PK Ruokojärvi P Rossi E Hanski A Päätalo K Vartiainen T 《Environmental science and pollution research international》2009,16(1):95-105
Background, aim, and scope The paper describes the spatial contamination of the River Kymijoki, South-Eastern Finland, and the coastal region of the
Gulf of Finland with PCDD/Fs and mercury. The findings of ecotoxicologial and human health studies are also reported, including
environmental and human risk assessments. Sediments from the River Kymijoki, draining into the Gulf of Finland, have been
heavily polluted by the pulp and paper industry and by chemical industries. A wood preservative, known as Ky-5, was manufactured
in the upper reaches of the river between 1940 and 1984 causing severe pollution of river sediments with polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF). Moreover, the sediments have been polluted with mercury (Hg) from chlor-alkali production
and the use of Hg as a slimicide in pulp and paper manufacturing.
Materials and methods An extensive sediment survey was conducted as well as sediment transport modeling, toxicity screening of sediment invertebrates,
and a survey of contaminant bioaccumulation in invertebrates and fish. Studies on human exposure to PCDD/Fs and the possible
effects on hypermineralization of teeth as well as an epidemiological study to reveal increased cancer risk were also conducted.
An assessment of the ecological and human health risks with a null hypothesis (no remediation) was undertaken.
Results The sediment survey revealed severe contamination of river and coastal sediments with PCDD/Fs and Hg. The total volume of
contaminated sediments was estimated to reach 5 × 106 m3 and hot spots with extremely high concentrations (max 292,000 ng g−1 or 1,060 ng I-TEQ g−1 d.w.) were located immediately downstream from the pollution source (approximately 90,000 m3). Sediment contamination was accompanied by changes in benthic assemblages, but direct effects were masked by many factors.
The fish showed only slightly elevated PCDD/F levels in muscle, but orders of magnitude higher in the liver compared with
reference freshwater sites and the Baltic Sea. The concentrations in human fat did not reveal high human exposure in the Kymijoki
area in general and was lower than in sea fishermen. The relative risk for total cancer among farmers was marginally higher
(RR = 1.13) among those living close to the river, compared with farmers living further away, and the possibility of increased
cancer risk cannot be ruled out. A conservative risk assessment revealed that the present probability of exceeding the WHO
upper exposure limit of 4 pg WHO-TEQ kg−1 d−1 for PCDD/Fs and DL-PCBs was 6%. The probability of exceeding the WHO limit value of 0.23 μg kg−1 d−1 for methyl mercury was estimated to be notably higher at 62%. Based on these studies and the estimated risks connected with
different remediation techniques a general remediation plan with cost benefit analysis was generated for several sub-regions
in the river. Dredging, on-site treatment, and a close disposal of the most contaminated sediments (90,000 m3) was suggested as the first phase of the remediation. The decision regarding the start of remediation will be made during
autumn 2008.
Conclusions The sediments in the River Kymijoki are heavily polluted with PCDD/Fs and mercury from earlier chlorophenol, chlor-alkali,
and pulp and paper manufacturing. A continuous transport of contaminants is taking place to the Gulf of Finland in the Baltic
Sea. The highly increased PCDD/F and Hg levels in river sediments pose an ecotoxicological risk to benthic fauna, to fish-eating
predators and probably to human health. The risks posed by mercury exceed those from PCDD/Fs and need to be evaluated for
(former) chlor-alkali sites and other mercury releasing industries as one basis for remediation decision making.
Recommendations and perspectives The studies form the basis of a risk management strategy and a plan for possible remediation of contaminated sediments currently
under consideration in the Southeast Finland Regional Environment Centre. It is recommended that a detailed restoration plan
for the most seriously contaminated areas should be undertaken. Based on current knowledge, the restoration of the whole river
is not feasible, considering the current risk caused by the contaminated sediment in the river and the costs of an extensive
restoration project. The experiences gained in the present case should be utilized in the evaluation of PCDD/F- and mercury-contaminated
sites in other countries. The case demonstrates that the historic reservoirs are of contemporary relevance and should be addressed,
e.g., in the national implementation plans of the Stockholm Convention.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
104.
This study dealt with in situ removal of copper from sediments through an electrokinetic (EK) process driven by a galvanic cell. Iron (Fe) and carbon (C) were placed separately and connected with a conductive wire. Polluted sediments were put between them and water was filled above the sediments. The galvanic cell was thus formed due to the different electrode potentials of Fe and C. The cell could remove the pollutants in the sediments by electromigration and/or electroosmosis. Results showed that a weak voltage less than 1V was formed by the galvanic cell. The voltage decreased with the increase of time. A slight increase of sediment pH from the anode (Fe) to the cathode (C) was observed. The presence of supernatant water inhibited the variation of sediment pH because H(+) and OH(-) could diffuse into the water. The removal of copper was affected by the sediment pH and the distribution of electrolyte in sediment and supernatant water. Lower pH led to higher removal efficiency. More electrolyte in the sediment and/or less electrolyte in the supernatant water favored the removal of copper. The major removal mechanism was proposed on the basis of the desorption of copper from sediment to pore solution and the subsequent electromigration of copper from the anode to the cathode. The diffusion of copper from sediment to supernatant water was negligible. 相似文献
105.
S.J. Sartandel S.K. Jha S.V. Bara R.M. Tripathi V.D. Puranik 《Journal of environmental radioactivity》2009,100(10):831-834
The understanding and evaluation of the possible interactions of various naturally occurring radionuclides in the world's third largest man-made dam, Nagarjuna Sagar located in Andhra Pradesh, India and built on river Krishna assumed significance with the finding of uranium deposits in locations near the dam. For the present work, surface soil samples from the mineralized area of Lambapur, Mallapuram, Peddagattu and sediment core samples from the Nagarjuna Sagar dam were analyzed for naturally occurring radionuclides namely uranium and thorium using gamma spectrometric technique. Also toxic elements lead and chromium were analysed by the Energy Dispersive X-ray Fluorescence Spectrometer (EDXRF) technique. Surface soil samples show a variation from 25 to 291 Bq/kg (2.02–23.5 mg/kg) for 238U and 32–311 Bq/kg (7.9–76.9 mg/kg) for 232Th. U/Th concentration ratio in surface soil samples ranged from 0.19 to 0.31 and was found comparable with the nation wise average of 0.26. The study of sediment core samples reflected higher U/Th concentration ratio of 0.30–0.33 in the bottom section of the core as compared to 0.22–0.25 in the upper section. The concentration ratio in the upper section of the core was similar to the ratio 0.23 found in the western Deccan Basalt region through which the river originates. A higher concentration of lead and chromium was observed in the upper section of the core compared to bottom section indicating the impact of river input on the geochemical character of dam sediment. 相似文献
106.
Spatial distribution of 238U and 226Ra activities in sediment columns along the Krka River and estuary, were studied using gamma spectrometry. Markedly different 238U and 226Ra activities between riverine, estuarine and marine sediments were observed. Distribution of these radionuclides, as well as their anthropogenic and natural origin, was evaluated by activity measurements, taking into account sedimentation rates estimated by 137Cs distribution in sediment columns. 相似文献
107.
108.
Degassing of H/He, CFCs and SF6 by denitrification: Measurements and two-phase transport simulations
Ate Visser Joris D. Schaap Hans Peter Broers Marc F.P. Bierkens 《Journal of contaminant hydrology》2009,103(3-4):206-218
The production of N2 gas by denitrification may lead to the appearance of a gas phase below the water table prohibiting the conservative transport of tracer gases required for groundwater dating. We used a two-phase flow and transport model (STOMP) to study the reliability of 3H/3He, CFCs and SF6 as groundwater age tracers under agricultural land where denitrification causes degassing. We were able to reproduce the amount of degassing (R2 = 69%), as well as the 3H (R2 = 79%) and 3He (R2 = 76%) concentrations observed in a 3H/3He data set using simple 2D models. We found that the TDG correction of the 3H/3He age overestimated the control 3He/3He age by 2.1 years, due to the accumulation of 3He in the gas phase. The total uncertainty of degassed 3H/3He ages of 6 years (± 2 σ) is due to the correction of degassed 3He using the TDG method, but also due to the travel time in the unsaturated zone and the diffusion of bomb peak 3He. CFCs appear to be subject to significant degradation in anoxic groundwater and SF6 is highly susceptible to degassing. We conclude that 3H/3He is the most reliable method to date degassed groundwater and that two-phase flow models such as STOMP are useful tools to assist in the interpretation of degassed groundwater age tracer data. 相似文献
109.
Geochemical processes of mercury in Wujiangdu and Dongfeng reservoirs, Guizhou, China 总被引:2,自引:0,他引:2
Xinbin Feng Hongmei Jiang Guangle Qiu Haiyu Yan Guanghui Li Zhonggen Li 《Environmental pollution (Barking, Essex : 1987)》2009,157(11):2970-2984
The geochemical processes of mercury in Dongfeng (DF) and Wujiangdu (WJD) reservoirs, which were constructed in 1992 and 1979, respectively in Wujiang River, which is the upper branch of Yangtze River were investigated. One sampling site was chosen upriver of 1 km from the dam for each reservoir. Three sampling campaigns were conducted at these sampling sites in December 2003, April 2004 and July 2004, respectively. The distributions of different mercury species in the water column, sediment, and sediment pore water were studied. We found that the sediment is the net source of both inorganic and MeHg to the water column for both reservoirs. The MeHg diffusion fluxes in WJD reservoir at all sampling campaigns were significantly higher than those in DF reservoir. Our study demonstrated that the high primary productivity in the reservoir produced elevated organic matter content that would favor the methylmercury production in sediment. 相似文献
110.
Incorporating layer- and local-scale heterogeneities in numerical simulation of unsaturated flow and tracer transport 总被引:1,自引:0,他引:1
Feng Pan Ming Ye Jianting Zhu Yu-Shu Wu Bill X. Hu Zhongbo Yu 《Journal of contaminant hydrology》2009,103(3-4):194-205
This study characterizes layer- and local-scale heterogeneities in hydraulic parameters (i.e., matrix permeability and porosity) and investigates the relative effect of layer- and local-scale heterogeneities on the uncertainty assessment of unsaturated flow and tracer transport in the unsaturated zone of Yucca Mountain, USA. The layer-scale heterogeneity is specific to hydrogeologic layers with layerwise properties, while the local-scale heterogeneity refers to the spatial variation of hydraulic properties within a layer. A Monte Carlo method is used to estimate mean, variance, and 5th, and 95th percentiles for the quantities of interest (e.g., matrix saturation and normalized cumulative mass arrival). Model simulations of unsaturated flow are evaluated by comparing the simulated and observed matrix saturations. Local-scale heterogeneity is examined by comparing the results of this study with those of the previous study that only considers layer-scale heterogeneity. We find that local-scale heterogeneity significantly increases predictive uncertainty in the percolation fluxes and tracer plumes, whereas the mean predictions are only slightly affected by the local-scale heterogeneity. The mean travel time of the conservative and reactive tracers to the water table in the early stage increases significantly due to the local-scale heterogeneity, while the influence of local-scale heterogeneity on travel time gradually decreases over time. Layer-scale heterogeneity is more important than local-scale heterogeneity for simulating overall tracer travel time, suggesting that it would be more cost-effective to reduce the layer-scale parameter uncertainty in order to reduce predictive uncertainty in tracer transport. 相似文献