全文获取类型
收费全文 | 1732篇 |
免费 | 17篇 |
国内免费 | 187篇 |
专业分类
安全科学 | 80篇 |
废物处理 | 107篇 |
环保管理 | 159篇 |
综合类 | 383篇 |
基础理论 | 393篇 |
环境理论 | 1篇 |
污染及防治 | 552篇 |
评价与监测 | 108篇 |
社会与环境 | 125篇 |
灾害及防治 | 28篇 |
出版年
2023年 | 17篇 |
2022年 | 55篇 |
2021年 | 21篇 |
2020年 | 12篇 |
2019年 | 22篇 |
2018年 | 66篇 |
2017年 | 34篇 |
2016年 | 48篇 |
2015年 | 73篇 |
2014年 | 55篇 |
2013年 | 152篇 |
2012年 | 73篇 |
2011年 | 90篇 |
2010年 | 83篇 |
2009年 | 85篇 |
2008年 | 91篇 |
2007年 | 78篇 |
2006年 | 64篇 |
2005年 | 65篇 |
2004年 | 86篇 |
2003年 | 88篇 |
2002年 | 56篇 |
2001年 | 123篇 |
2000年 | 55篇 |
1999年 | 33篇 |
1998年 | 24篇 |
1997年 | 14篇 |
1996年 | 15篇 |
1995年 | 24篇 |
1994年 | 10篇 |
1993年 | 12篇 |
1992年 | 18篇 |
1991年 | 11篇 |
1990年 | 14篇 |
1989年 | 11篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 8篇 |
1984年 | 10篇 |
1983年 | 7篇 |
1980年 | 6篇 |
1975年 | 8篇 |
1974年 | 10篇 |
1973年 | 7篇 |
1972年 | 12篇 |
1966年 | 5篇 |
1965年 | 5篇 |
1959年 | 5篇 |
1957年 | 5篇 |
排序方式: 共有1936条查询结果,搜索用时 15 毫秒
41.
42.
Multivariate statistical study of heavy metal enrichment in sediments of the Pearl River Estuary 总被引:33,自引:0,他引:33
Liu WX Li XD Shen ZG Wang DC Wai OW Li YS 《Environmental pollution (Barking, Essex : 1987)》2003,121(3):377-388
The concentrations and chemical partitioning of heavy metals in the sediment cores of the Pearl River Estuary were studied. Based on Pearson correlation coefficients and principal component analysis results, Al was selected as the concentration normalizer for Pb, while Fe was used as the normalizing element for Co, Cu, Ni and Zn. In each profile, sections with metal concentrations exceeding the upper 95% prediction interval of the linear regression model were regarded as metal enrichment layers. The heavy metal accumulation mainly occurred at sites in the western shallow water areas and east channel, which reflected the hydraulic conditions and influence from riparian anthropogenic activities. Heavy metals in the enrichment sections were evaluated by a sequential extraction method for possible chemical forms in sediments. Since the residual, Fe/Mn oxides and organic/sulfide fractions were dominant geochemical phases in the enriched sections, the bioavailability of heavy metals in sediments was generally low. The 206Pb/207Pb ratios in the metal-enriched sediment sections also revealed the influence of anthropogenic sources. The spatial distribution of cumulative heavy metals in the sediments suggested that the Zn and Cu mainly originated from point sources, while the Pb probably came from non-point sources in the estuary. 相似文献
43.
Fate and assessment of persistent organic pollutants in water and sediment from Minjiang River Estuary,Southeast China 总被引:56,自引:0,他引:56
Persistent organochlorine compounds were analyzed in surface water, porewater and surficial sediment samples from Minjiang River Estuary, which is the first large river in Fujian Province, Southeast of China. The total concentrations of 18 organochlorine pesticides were 214.4-1819, 4541-13,699 ng/l, 28.79-52.07 ng/g in surface water, porewater and sediments (dry weight) respectively, and those of 21 polychlorinated biphenyls (PCBs) in the three phases were: 203.9-2473, 3192-10,855 ng/l, 15.14-57.93 ng/g respectively. The results showed that the concentrations of these selected organochlorine pesticides and PCBs in porewater were higher than those in surface water. It may be due to the fact that these organic hydrophobic pollutants tend to stay in the sediments, and then re-suspend from the sedimentary phase to the upper water. We have analyzed the distribution characteristics of individual organochlorine pesticide components and PCBs, and found that alpha-HCH, DDE, Heptachlor, Endosulfan II, Methoxychlor were the most common organochlorine pesticides contaminants. Considering the groups of HCHs (HCHs=alpha-HCH+beta-HCH+gamma-HCH+delta-HCH) and DDTs (DDTs=DDT+DDD+DDE), the predominance of beta-HCH, DDE in all water, porewater and sediment samples was clearly observed. This observation suggested that beta-HCH was resistant to biodegradation and the DDTs had been transformed to its metabolites, DDE and DDD, of which DDE that was more un-degradable. The PCB congeners containing 3-6 chlorines had the great preponderance in the three phase. These results were compared with those present in other estuaries and harbors. A risk assessment was evaluated for the persistent organic pollutants in the Minjiang River Estuary. 相似文献
44.
Status of trace elements in paddy soil and sediment in Taihu Lake region 总被引:14,自引:0,他引:14
Thirteen paddy soil profiles and river sediments which are sources of irrigation water were collected around the Taihu Lake, and the trace elements were estimated. The content of La and Ce in paddy soil and sediment were 39.3 and 68.6 mg/kg soil and 36.9 and 65.1 mg/kg soil, being within the range of background values. The values for Pb, Cu, Ni, Cr, Co, Mn, Zn, Se in paddy soil were 23.3, 27.8, 25.5, 63.5, 10.2, 386, 68.7 and 0.25 mg/kg soil respectively, all below the national permission level. There was a decline of Zn in paddy soil. Some of the river sediments were seriously polluted. The river in Yangjin site was most contaminated with 5.47 g Cu/kg and 7.4 g Zn/kg. The high concentration of Pb and Ni also was observed in this sediment. River in Weitang, Huashi, Xinzhuang and Meiyan were contaminated with Pb, Cu and Ni to some extent. Zn, Cu and Pb were the main pollutants in present experiment sites. The fast development of village/township industries have caused severe environmental pollution in the Taihu Lake region, especially irrigation river sediments. Se content in plant and seed was 0.04 and 0.03 mg/kg respectively, showed Se-deficiency in paddy soil in the Taihu Lake region. 相似文献
45.
Alessandra A. Z. Rodrigues André Fernando De Oliveira Antônio Augusto Neves Fernanda F. Heleno Laércio Zambolim 《Journal of environmental science and health. Part. B》2017,52(12):850-857
This study was undertaken to evaluate the effectiveness of several household practices (washing with water or acidic, alkaline, and oxidizing solutions, and peeling) in minimizing pesticide residue contamination of tomatoes, as well as the impact on the quality of the treated fruit. Tests were performed using two systemic fungicides (azoxystrobin and difenoconazole) and one contact fungicide (chlorothalonil). Solid-liquid extraction with low temperature partition (SLE/LTP) and liquid-liquid extraction with low temperature partition (LLE/LTP) were used to prepare the samples for pesticides determination by gas chromatography. Washing the tomatoes with water removed approximately 44% of chlorothalonil, 26% of difenoconazole, and 17% of azoxystrobin. Sodium bicarbonate (5%) and acetic acid (5%) solutions were more efficient, removing between 32 and 83% of the residues, while peeling removed from 68 to 88% of the pesticides. The washing solutions altered some fruit quality parameters, including acidity and chroma, and also caused weight loss. Acetic acid (0.15 and 5%) and hypochlorite (1%) solutions had the greatest effect on these parameters. 相似文献
46.
47.
湖南某造纸厂采用二相厌氧 混凝法处理制浆造纸综合废水取得了显著效果 ,CODCr排放总量削减率达 80 % ,水体水质明显改善。本文介绍了该工程的工艺设计及调试。 相似文献
48.
The velocity of DNAPL fingering in water-saturated porous media: laboratory experiments and a mobile-immobile-zone model. 总被引:2,自引:0,他引:2
Dense nonaqueous phase liquids (DNAPLs) are immiscible with water and can give rise to highly fingered fluid distributions when infiltrating through water-saturated porous media. In this paper, a conceptual mobile-immobile-zone (MIZ) model is presented to describe the structure of a DNAPL finger in water-saturated porous media and the velocity of finger propagation. A finger is composed of a finger body and a tip. The finger body has a mobile core and an immobile sheath. All the DNAPL within the tip of a finger is mobile. Lab experiments utilizing image analyses of a DNAPL (PCE) penetrating into water-saturated homogeneous glass beads were carried out in a two-dimensional transparent chamber. The results show that the fingers elongated almost linearly with time. The fingers did not grow laterally after the tip of the finger had passed. The average finger diameters were between 3.9 and 5.4 mm for PCE propagation in water-saturated glass bead porous media with mean particle diameters from 0.32 to 1.36 mm. The estimated mobile core diameters were 51-60% of the average finger diameters. 相似文献
49.
Precipitation chemistry in the coast of the Metropolitan Region of Rio de Janeiro, Brazil 总被引:1,自引:0,他引:1
de Mello WZ 《Environmental pollution (Barking, Essex : 1987)》2001,114(2):235-242
Precipitation chemistry was studied in the Metropolitan Region of Rio de Janeiro (MRRJ). This study reveals that rainwater in the MRRJ is affected by emissions of air pollutants and provides essential data for future estimates of regional biogeochemical cycles and the impacts of acid deposition on tropical ecosystems. The volume-weighted mean (VWM) pH was 4.77, varying from 3.50 to 6.85. Sea-salt aerosols were the dominant sources of the Na+, Cl- and Mg2+. Excess SO4(2-), Ca2+ and K+ comprised 82, 91, and 87% of their total VWM concentrations, respectively. There were very strong correlations (r > 0.75, P > 0.01) for NO3- and H+, NO3- and excess(exc-)SO4(2-), NH4+ and exc-K+, and exc-SO4(2-) and exc-Ca2+, suggesting causal relationships between these ion pairs. The VWM concentrations of all major ions, except H+, were higher in the dry season, with dry to wet VWM concentration ratios varying from 1.1 (NH4+) to 4.7 (for total K+). 相似文献
50.
Min H Ye YF Chen ZY Wu WX Yufeng D 《Journal of environmental science and health. Part. B》2001,36(5):581-595
This paper reports the influences of the herbicide butachlor (n-butoxymethlchloro -2', 6'-diethylacetnilide) on microbial populations, respiration, nitrogen fixation and nitrification, and on the activities of dehydrogenase and hydrogen peroxidase in paddy soil. The results showed that the number of actinomycetes declined significantly after the application of butachlor at different concentrations ranging from 5.5 microg g(-1) to 22.0 microg g(-1) dried soil, while that of bacteria and fungi increased. Fungi were easily affected by butachlor compared to the bacteria. The growth of fungi was retarded by butachlor at higher concentrations. Butachlor however, stimulated the growth of anaerobic hydrolytic fermentative bacteria, sulfate-reducing bacteria (SRB) and denitrifying bacteria. The increased concentration of butachlor applied resulted in the higher number of SRB. Butachlor inhibited the growth of hydrogen-producing acetogenic bacteria. The effect of butachlor varied on methane-producing bacteria (MPB) at different concentrations. Butachlor at the concentration of 1.0 microg g(-1) dried soil or less than this concentration accelerated the growth of MPB, while at 22.0 microg g(-1) dried soil showed an inhibition. Butachlor enhanced the activity of dehydrogenase at increasing concentrations. The soil dehydrogenase showed the highest activity on the 16th day after application of 22.0 microg g(-1) dried soil of butachlor. The hydrogen peroxidase could be stimulated by butachlor. The soil respiration was depressed during the period from several days to more than 20 days, depending on concentrations of butachlor applied. Both the nitrogen fixation and nitrification were stimulated in the beginning but reduced greatly afterwards in paddy soil. 相似文献