全文获取类型
收费全文 | 1646篇 |
免费 | 16篇 |
国内免费 | 40篇 |
专业分类
安全科学 | 23篇 |
废物处理 | 113篇 |
环保管理 | 157篇 |
综合类 | 139篇 |
基础理论 | 297篇 |
环境理论 | 2篇 |
污染及防治 | 557篇 |
评价与监测 | 302篇 |
社会与环境 | 107篇 |
灾害及防治 | 5篇 |
出版年
2023年 | 64篇 |
2022年 | 173篇 |
2021年 | 119篇 |
2020年 | 25篇 |
2019年 | 47篇 |
2018年 | 82篇 |
2017年 | 88篇 |
2016年 | 112篇 |
2015年 | 45篇 |
2014年 | 78篇 |
2013年 | 177篇 |
2012年 | 77篇 |
2011年 | 90篇 |
2010年 | 72篇 |
2009年 | 61篇 |
2008年 | 74篇 |
2007年 | 54篇 |
2006年 | 62篇 |
2005年 | 35篇 |
2004年 | 23篇 |
2003年 | 22篇 |
2002年 | 28篇 |
2001年 | 8篇 |
2000年 | 7篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 7篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1979年 | 2篇 |
1969年 | 1篇 |
1966年 | 1篇 |
1965年 | 2篇 |
1964年 | 2篇 |
1962年 | 2篇 |
1961年 | 4篇 |
1958年 | 3篇 |
1957年 | 3篇 |
1956年 | 2篇 |
1955年 | 4篇 |
1953年 | 1篇 |
排序方式: 共有1702条查询结果,搜索用时 15 毫秒
531.
Uttam Kumar Sarkar Vineet Kumar Dubey Atul Kumar Singh Brij Kishor Gupta Ajay Pandey Rupali Kumar Sani Wazir Singh Lakra 《The Environmentalist》2012,32(4):476-484
We record here the recent occurrence, abundance and distribution of six exotic fish species, viz. Oreochromis mossambicus, Cyprinus carpio, Hypopthalmicthys molitrix, Ctenopharyngodon idellus, Clarias gariepinus, and Pterygoplichthys disjunctivus (a new exotic in India) distributed through the four important tributaries of river Ganga basin in India. From the total catch, the abundance index of all exotic species in different rivers ranged from 1.1 to 14.5?% with highest value in River Gomti. The relative abundance of the exotic species in all the four tributaries demonstrated that a single species C. carpio contributed a considerable abundance (43.3?C83?%) than that of the remaining exotic fishes. The Common Carp, C. carpio, was ubiquitous in all the four tributaries of Ganges basin studied and had the highest local distribution (52.63?%). Smaller size groups of endangered (Chagunius chagunio, Chitala chitala, and Tor tor) and migratory species (Bagarius bagarius, Ompok pabda, Wallago attu, and Sperata aor) in the four tributaries were recorded, and the increasing appearance of Common Carp and other exotic fishes is signaling biological invasion. Possible threats to the indigenous fish fauna, as a result of the invasion and proliferation of these exotics, are discussed. 相似文献
532.
Assessment of habitat quality with relation to fish assemblages in an impacted river of the Ganges basin, northern India 总被引:1,自引:0,他引:1
In this work, we examined water-quality assessment in relation to fish assemblage of Gomti River, a large tributary of the
Ganges River basin in northern India. Principal component analysis was performed for 18 environmental variables which produced
three axes that cumulatively explained 60.23% of the environmental variation in sites. Fifteen variables (fine substrate fine
gravel, coarse gravel, cobble, sand substrate water flow, conductivity, TDS, total hardness, temperature, dissolved oxygen,
pH, and overhanging vegetation) had high loadings on at least one of the principal component axes interpreted. The canonical
correspondence analysis was used to establish the relationship between important fish species and environmental variables.
Species were distributed within four groups with respect to the significant habitat characteristics. The Pearson correlation
coefficient was calculated between the water-quality parameters. We concluded that the level of species richness is mostly
dependent on abiotic factors like temperature, dissolved oxygen, TDS, conductivity, depth, pH, and water current in the Gomti
River, of the Ganges basin. 相似文献
533.
In relation to fluoride in ground water, dental fluorosis is studied in seven villages, viz., Nasipur, Vabanandapur, and Deshnabagram
under Nalhati I block and Kamdebpur, Chalk Atla, Nowapara, and Junitpur under Rampurhat II block, of Birbhum district, West
Bengal, India. Water samples (N = 70) were collected from the tube wells of the mentioned villages in the months of December 2010 to February 2011 and analyzed
for fluoride and other water parameters. The study result revealed that the fluoride levels of almost all the water samples
(95.7%) were higher than 1.5 mg/L, with mean values of 3.15 and 3.83 mg/L in Nalhati I block and Rampurhat II block, respectively.
Dental fluorosis of 490 respondents was visually determined by a competent dentist using Dean’s index (DI) and the tooth surface
index of fluorosis (TSIF). According to the DI, the percentage of severely affected respondents was lowest in Chalk Atla (0%)
and highest in Deshnabagram (50%). The percentage of severely affected respondents was lowest in Kamdebpur and Chalk Atla
(0%) and highest in Nowapara (20%) according to the TSIF score. The age group 10–20 years showed the highest percentage of
severe DI (40.8%) and the age group 21–30 years showed the highest percentage of severe TSIF (22.51%) compared to the other
age groups in the study. The positive relationship between the fluoride level in water and the severity of dental fluorosis
has been proved statistically. The high mean score of dental fluorosis indicates that dental fluorosis is endemic throughout
the study area. 相似文献
534.
Solvent tolerant marine bacterium Bacillus aquimaris secreting organic solvent stable alkaline cellulase 总被引:1,自引:0,他引:1
The organic solvent tolerant bacteria with their physiological abilities to decontaminate the organic pollutants have potentials to secrete extracellular enzymes of commercial importance. Of the 19 marine bacterial isolates examined for their solvent tolerance at 10 vol.% concentration, one had the significant tolerance and showed a relative growth yield of 86% for acetone, 71% for methanol, 52% for benzene, 35% for heptane, 24% for toluene and 19% for ethylacetate. The phylogenetic analysis of this strain using 16S rDNA sequence revealed 99% homology with Bacillus aquimaris. The cellulase enzyme secreted by this strain under normal conditions showed an optimum activity at pH 11 and 45 °C. The enzyme did show functional stability even at higher pH (12) and temperature (75 °C) with residual activity of 85% and 95% respectively. The enzyme activity in the presence of different additives were in the following order: Co+2 > Fe+2 > NaOCl2 > CuSO4 > KCl > NaCl. The enzyme stability in the presence of solvents at 20 vol.% concentration was highest in benzene with 122% followed by methanol (85%), acetone (75%), toluene (73%) and heptane (42%). The pre-incubation of enzyme in ionic liquids such as 1-ethyl-3-methylimidazolium methanesulfonate and 1-ethyl-3-methylimidazolium bromide increased its activity to 150% and 155% respectively. The change in fatty acid profile with different solvents further elucidated the physiological adaptations of the strain to tolerate such extreme conditions. 相似文献
535.
In 2007, a program was initiated to monitor air levels of volatile organic compounds (VOCs) and bioaerosols in the vicinity of a municipal solid waste incinerator (MSWI) (Tarragona, Catalonia, Spain). To investigate the temporal trends of chemical and microbiological pollutants, four 6-monthly campaigns were performed. Air samples were collected at different distances and directions from the facility, as well as in reference sites. In general terms, the concentrations of microbiological agents were very similar to those found in urban zones worldwide. The seasonal evaluation of the results showed higher levels of gram-negative bacteria in winter, contrasting with the increase of the airborne amount of total bacteria in summer. On the other hand, the concentrations of VOCs (mean range: 7.6-18.2 μgm−3) were typical of suburban zones. The current exposure to those compounds should not mean additional health risks for the population living nearby. 相似文献
536.
Organochlorine pesticides (OCPs) have been beneficial to man and environment but their inadvertent use has caused considerable harm to human health. Despite the proliferation of different types of pesticides, organochlorines such as HCH and DDT still account for two third of the total consumption in India because of their low cost and versatility in action again various pests. Since, Assam, a state in North-eastern part of India is an endemic area with perennial transmission where mosquito borne diseases are serious health problems; these pesticides are still being used in huge quantities in vector control as well as in agriculture. A total of 331 human blood samples were collected from district Nagaon and Dibrugarh of Assam to determine the residue levels of DDT and HCH in human blood. The concentrations of selected persistent organochlorine pollutants were measured with gas chromatography-electron capture detector. The results demonstrated that the mean levels of total DDT and HCH were 743 μg L(-1) and 627 μg L(-1) for district Nagaon while 417 μg L(-1) and 348 μg L(-1) for district Dibrugarh. The difference of total HCH and total DDT between these two districts was found to be highly significant (P<0.0001). Among DDT metabolites, the same trend was observed for both the districts as p,p-DDT was the principal component contributed 41% for Nagaon and 58% for Dibrugarh. In case of HCH residues, for Nagaon, β-HCH was the predominant contaminant comprised more than 34% while for Dibrugarh, it was α-HCH that was contributing 43% of total HCH concentration. 相似文献
537.
An overview of experimental results and dispersion modelling of nanoparticles in the wake of moving vehicles 总被引:1,自引:0,他引:1
Understanding the transformation of nanoparticles emitted from vehicles is essential for developing appropriate methods for treating fine scale particle dynamics in dispersion models. This article provides an overview of significant research work relevant to modelling the dispersion of pollutants, especially nanoparticles, in the wake of vehicles. Literature on vehicle wakes and nanoparticle dispersion is reviewed, taking into account field measurements, wind tunnel experiments and mathematical approaches.Field measurements and modelling studies highlighted the very short time scales associated with nanoparticle transformations in the first stages after the emission. These transformations strongly interact with the flow and turbulence fields immediately behind the vehicle, hence the need of characterising in detail the mixing processes in the vehicle wake. Very few studies have analysed this interaction and more research is needed to build a basis for model development. A possible approach is proposed and areas of further investigation identified. 相似文献
538.
Hettiarachchi VC Hettiaratchi PJ Mehrotra AK Kumar S 《Environmental pollution (Barking, Essex : 1987)》2011,159(6):1715-1720
Methane biofiltration (MBF) is a novel low-cost technique for reducing low volume point source emissions of methane (CH4). MBF uses a granular medium, such as soil or compost, to support the growth of methanotrophic bacteria responsible for converting CH4 to carbon dioxide (CO2) and water (H2O). A field research program was undertaken to evaluate the potential to treat low volume point source engineered CH4 emissions using an MBF at a natural gas monitoring station. A new comprehensive three-dimensional numerical model was developed incorporating advection-diffusive flow of gas, biological reactions and heat and moisture flow. The one-dimensional version of this model was used as a guiding tool for designing and operating the MBF. The long-term monitoring results of the field MBF are also presented. The field MBF operated with no control of precipitation, evaporation, and temperature, provided more than 80% of CH4 oxidation throughout spring, summer, and fall seasons. The numerical model was able to predict the CH4 oxidation behavior of the field MBF with high accuracy. The numerical model simulations are presented for estimating CH4 oxidation efficiencies under various operating conditions, including different filter bed depths and CH4 flux rates. The field observations as well as numerical model simulations indicated that the long-term performance of MBFs is strongly dependent on environmental factors, such as ambient temperature and precipitation. 相似文献
539.
Kumar V Nakada N Yamashita N Johnson AC Tanaka H 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2906-2912
A detailed study of the free and conjugated estrogen load discharged by the eight major sewage treatment plants into the Yodo River basin, Japan was carried out. Sampling campaigns were focused on the winter and autumn seasons from 2005 to 2008 and the free estrogens estrone(E1), 17β-estradiol(E2), estriol(E3), 17α-ethynylestradiol(EE2) as well as their conjugated (sulfate and glucuronide) forms. For both sewage effluent and river water E2 and E1 concentrations were greatest during the winter period (December-March). This coincides with the period of lowest rainfall and lowest temperatures in Japan. E1 was the dominant estrogenic component in effluent (means of 10-50 ng/L) followed by E2 (means of 0.5-3 ng/L). The estrogen sulfate conjugates were found intermittently in the 0.5-1.7 ng/L concentration range in the sewage effluents. The greatest estrogen exposure was found to be in the Katsura River tributary which exceeded 1 ng/L E2-equivalents during the winter period. 相似文献
540.
Stress-strain response of plastic waste mixed soil 总被引:1,自引:0,他引:1
Recycling plastic waste from water bottles has become one of the major challenges worldwide. The present study provides an approach for the use plastic waste as reinforcement material in soil. The experimental results in the form of stress-strain-pore water pressure response are presented. Based on experimental test results, it is observed that the strength of soil is improved and compressibility reduced significantly with addition of a small percentage of plastic waste to the soil. The use of the improvement in strength and compressibility response due to inclusion of plastic waste can be advantageously used in bearing capacity improvement and settlement reduction in the design of shallow foundations. 相似文献