全文获取类型
收费全文 | 737篇 |
免费 | 57篇 |
国内免费 | 243篇 |
专业分类
安全科学 | 44篇 |
废物处理 | 11篇 |
环保管理 | 51篇 |
综合类 | 453篇 |
基础理论 | 191篇 |
污染及防治 | 134篇 |
评价与监测 | 116篇 |
社会与环境 | 34篇 |
灾害及防治 | 3篇 |
出版年
2024年 | 1篇 |
2023年 | 24篇 |
2022年 | 31篇 |
2021年 | 32篇 |
2020年 | 34篇 |
2019年 | 33篇 |
2018年 | 28篇 |
2017年 | 31篇 |
2016年 | 46篇 |
2015年 | 30篇 |
2014年 | 34篇 |
2013年 | 78篇 |
2012年 | 45篇 |
2011年 | 63篇 |
2010年 | 44篇 |
2009年 | 37篇 |
2008年 | 54篇 |
2007年 | 42篇 |
2006年 | 36篇 |
2005年 | 32篇 |
2004年 | 32篇 |
2003年 | 24篇 |
2002年 | 30篇 |
2001年 | 22篇 |
2000年 | 25篇 |
1999年 | 21篇 |
1998年 | 26篇 |
1997年 | 10篇 |
1996年 | 16篇 |
1995年 | 16篇 |
1994年 | 12篇 |
1993年 | 14篇 |
1992年 | 11篇 |
1991年 | 2篇 |
1990年 | 10篇 |
1989年 | 4篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1976年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有1037条查询结果,搜索用时 46 毫秒
491.
492.
To meet the rapidly growing global demand for aquaculture products, large amounts of antibiotics were used in aquaculture, which might accelerate the evolution of antibioticresistant bacteria(ARB) and the propagation of antibiotic genes(ARGs). In our research, we revealed the ARGs profiles, their co-occurrence with mobile genetic elements(MGEs), and potential hosts in sediments of a crab pond wastewater purification system based on metagenomic analysis. The residual antibiotic seems to increase ... 相似文献
493.
秃杉人工林营养元素含量、积累与分配特征的研究 总被引:9,自引:0,他引:9
对广西南丹山口林场秃杉人工林的N、P、K、Ca和Mg等5种营养元素含量、积累和分配及其随林分年龄的变化趋势进行了研究。结果表明,不同组分营养元素含量大小次序为树叶>干皮>树枝>树根>干材;林木各组分营养元素含量以N,Ca或K最高,其次是P,Mg最低。8、14和28年生林分营养元素积累总量分别为574.79、833.21和1214.11kg·hm–2,其中乔木层营养元素积累量依次占92.87%、86.74%和85.88%,林下植被层依次占2.02%、2.99%和4.62%,地表现存凋落物层依次占5.11%、10.27%和9.50%;乔木层均以N或Ca积累量最多,Mg最少;秃杉人工林不同组分营养元素积累量的分配随林分年龄的增长发生变化,由8年生和14年生以树叶和树枝为主,逐渐转移到28年生以干材和树皮为主。3个林分年龄秃杉林每积累1t干物质需要5种营养元素总量分别为8.97、6.40和4.21kg,其中对N或Ca的需求量最大,Mg最少。 相似文献
494.
Geochemistry of the barkinite liptobiolith (Late Permian) from the Jinshan Mine,Anhui Province,China
This paper discusses the geochemistry and mineralogy of the barkinite liptobiolith of the Late Permian age from the Jinshan
Mine, Guangde County, Anhui Province, China. Samples were examined using inductively coupled plasma-mass spectroscopy, X-ray
fluorescence, cold-vapor atomic absorption spectrometry, ion-selective electrode, sequential chemical extraction, scanning
electron microscopy equipped with energy-dispersive X-ray, and optical microscopy. The coal is a medium-ash and high-sulfur
resource. Minerals in the coal are composed of kaolinite, pyrite, calcite, and quartz. Pyrite and calcite are derived from
seawater during peat accumulation. Quartz in the coal is of authigenic origin. Part of the kaolinite is from a land-source
region, and part occurs as cell-fillings and is of authigenic origin. The results also indicate that the barkinite liptobiolith
contains some toxic elements in high concentrations. Elements including Li, Be, Si, Sc, Ti, V, Cr, Fe, Ga, Se, Y, Zr, Mo,
the rare earth elements (REEs), W, Hg, Tl, Pb, Th, and U in the coals are enriched in the barkinite liptobiolith. Results
of sequential chemical extraction showed that Li, Sc, Ti, Cr, Y, Zr, REEs, and Th in the coal mainly occur as silicates, while
Be and W are related to organic matter. Pyrite is the dominant source of S, Mo, Hg, Tl, and Pb. Gallium only occurs in silicate,
and U and V occur both in organic and silicate associations. 相似文献
495.
496.
典型铝塑厂周边土壤重金属分布特征与健康风险评价 总被引:1,自引:0,他引:1
为探究铝塑园区周边土壤重金属污染情况,选取山东省某城市塑料开发区为研究区,按照分层采样方式获取到80个土壤样品,分别测定土壤中As、Cd、Hg、Cr、Cu、Ni、Pb、Zn含量,运用统计分析法探讨土壤重金属等的分布特征和来源,并利用健康风险评价模型确定了土壤重金属对周边居民的健康风险。结果表明:As、Cd、Hg、Cr、Cu、Ni、Pb和Zn均超出山东省土壤背景值,其中Cd、Hg、Cu和Pb分别超出背景值48. 15%、106. 90%、62. 04%和39. 96%,表明土壤中存在一定程度的重金属积累,在周边140~210 m处最为严重,且受人类活动影响强烈,与风向关系不大;土壤重金属垂直分布特征大致呈现随着深度的增加不断增加,在20 cm深度附近达到最高值,其后不断降低并趋于平稳,Cd、Hg、Cu、Pb和Zn变异幅度大,受到人为干扰较大,As、Cr和Ni主要受成土母质控制,属于自然来源,变动幅度较小;研究区内8种元素不存在非致癌风险,Cr、As、Ni和Cd产生的致癌风险处在可接受范围内,但存在的潜在致癌风险应引起足够的重视。 相似文献
497.
Marcela Capcarova Lubos Harangozo Tomas Toth Loretta Schwarczova Alica Bobkova Robert Stawarz 《Journal of environmental science and health. Part. B》2017,52(12):858-863
The objective of this study was to determine the concentrations of Cu, Cd, Pb, Mn, Cr, Co, Ni, Zn, and Hg in the white and fruit parts of commercially available yogurts (n = 30) from Nitra markets (Slovak Republic). The results were correlated to determine their relationships. Three yogurt fruit flavors were chosen and tested, strawberry (n = 10), blueberry (n = 10), and cherry (n = 10). The elements were analyzed using atomic absorption spectrophotometry. Higher concentrations of toxic elements, such as Cd and Pb, were found in the fruit parts of the yogurt, and in some cases, the tolerable limit was exceeded. The white part of the yogurt was not contaminated by toxic elements. White yogurt is a good source of nutrients for humans, but the fruit part in yogurt requires detailed monitoring and improvements in the processing techniques. 相似文献
498.
Cram S Ponce De León CA Fernández P Sommer I Rivas H Morales LM 《Environmental monitoring and assessment》2006,121(1-3):127-149
Possible contaminants produced by the Petroleos Mexicanos (PEMEX) marine oil complex in the vicinity of the Cayo Arcas (Mexico) coral reef ecosystem were evaluated by analyzing sediments and sea water for hydrocarbons and metal elements. We found that the concentrations of aliphatic hydrocarbons in the sea water were generally low, with the highest values detected near the oil station; the concentration of polycyclic aromatic hydrocarbons (PAHs) was generally below the detection limit. The hydrocarbons found in the sediments seem to have a pyrogenic origin, and were probably produced by marine traffic in the study area. The total PAH concentration did not exceed the NOAA criteria, although levels of some individual PAHs did. The only metal detected in the sea water at high concentrations was nickel. The Ni/V ratio in the sediments indicates the contribution of crude oil to the system. The high content of Ni and Zn was attributed to the ballast waters from the oil tankers that load at the station's monobuoys. The presence of fine sediments that commonly originate from terrestrial ecosystems supported this assumption. 相似文献
499.
Raeymaekers B 《Environmental monitoring and assessment》2006,116(1-3):233-243
In order to establish a monitoring method to track long term changes of the amount of anthropogenic contamination in a district
of Bavaria (Germany), a biomonitoring campaign with honey bees was performed in spring 2002. Expected anomalies from the industry
or from residential areas in the sampled district could not be detected. An anomaly over a considerable part of the sampling
area correlating with other phenomena lead to the hypothesis of a prehistoric cosmic impact. Moreover a principal component
analysis of the data showed evidence for a biogenic, an anthropogenic and an unknown component hypothetically related to a
possible cosmic impact. 相似文献
500.
Introduction of the Factor of Partitioning in the Lithogenic Enrichment Factors of Trace Element Bioaccumulation in Plant Tissues 总被引:1,自引:0,他引:1
Bioindicators are widely used in the study of trace elements inputs into the environment and great efforts have been conducted to separate atmospheric from soil borne inputs on biomass accumulation. Many monitoring studies of trace element pollution take into account the dust particles located in the plant surface plus the contents of the plant tissues. However, it is usually only the trace element content in the plant tissues that is relevant on plant health. Enrichment factor equations take into account the trace element enrichment of biomasses with respect soil or bedrocks by comparing the ratios of the trace element in question to a lithogenic element, usually Al. However, the enrichment equations currently in use are inadequate because they do not take into account the fact that Al (or whichever reference element) and the element in question may have different solubility-absorption-retention levels depending on the rock and soil types involved. This constrain will become critical when results from different sites are compared and so in this article we propose that the solubility factors of each element are taken into account in order to overcome this constrain. We analysed Sb, Co, Ni, Cr, Pb, Cd, Mn, V, Zn, Cu, As, Hg, and Al concentration in different zones of Catalonia (NE Spain) using the evergreen oak Quercus ilex and the moss Hypnum cupressiforme as target species. We compared the results obtained in rural and non industrial areas with those from the Barcelona Metropolitan Area. We observed differences in Al concentrations of soils and bedrocks at each different site, together with the differences in solubility between Al and the element in question, and a weak correlation between total soil content and water extract content through different sites for most trace elements. All these findings show the unsuitability of the current enrichment factors for calculating lithospheric and atmospheric contributions to trace element concentrations in biomass tissues. The trace element enrichment factors were calculated by subtracting the part predicted by substrate composition (deduced from water extracts from soils and bedrock) from total concentrations. Results showed that for most of the trace elements analysed, trace elements enrichment factors were higher inside the Barcelona Metropolitan Area than outside, a finding that indicates that greater atmospheric inputs occur in urban areas. The results show that the most useful and correct way of establishing a reference for lithospheric and atmospheric inputs into the plant tissues is, first, to analyse samples of the same plant species collected from a number of sites possessing similar environmental conditions (climate, vegetation type, soil type) and, second, to use this new enrichment factor obtained by subtracting from the total concentration in plant tissue the predicted contribution of soil or bedrock extracts instead of that of total soil or bedrock concentrations. 相似文献