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481.
Proliferation of Glycogen Accumulating Organisms (GAOs) accounts as one of the major bottlenecks in biological phosphorus removal systems. GAO outcompeting polyphosphate accumulating organisms (PAOs) results in lower P-removal. Thus, finding optimal conditions that favour PAO in front of GAO is a current focus of research. This work shows how nitrite can provide a novel strategy for PAO enrichment. A propionate-fed GAO-enriched biomass (70% Defluviicoccus I, 18% Defluviicoccus II and 10% PAO) was subjected more than 50 d under anaerobic-anoxic conditions with nitrite as electron acceptor. These operational conditions led to a PAO-enriched sludge (85%) where GAO were washed out of the system (<10%), demonstrating the validity of the new approach for PAO enrichment. In addition, the presented suppression of Defluviicocus GAO with nitrite represents an add-on benefit to the nitrite-based systems since the proliferation of non-desirable GAO can be easily ruled out and added to the other benefits (i.e. lower aeration and COD requirements). 相似文献
482.
Arun Kumar 《生态毒理学报》2001,23(3):28-30
[1]Parikh,J.and S.Gokam(1993)Global Environment Change,Sepember,pp.276-91
[2]Painuly,J.P,K.Bhattachrya and J.Parkh(1997)Proceedings of AIJconference ed.Kalipada Chaterjee,ISBN 81-7525-043-7,P.145. 相似文献
483.
Geochemical study of groundwater from a structurally deformed granitic terrain near Hyderabad (India) was carried out to understand
and evaluate the hydrogeochemical processes and quality of groundwater. Several trace elements (Fe, Mn, Be, Al, V, Cr, Co,
Ni, Cu, Zn, As, Sr, Mo, Cd, Sb, Ba, Pb, U) along with major ions and minor elements were precisely estimated in shallow and
drilled wells to know the suitability of water for drinking and irrigation purposes. Analytical data shows that pH and major
ion chemistry in dug wells and bore wells do not vary significantly, while some trace elements (Fe, Mn, Al, Be, Co, Pb, U
and Zn) vary in dug wells and bore wells, which can be attributed to differential mineral weathering and dissolution/precipitation
reactions along fractures/joints. Although the water is not potable, it was found to be suitable for irrigation with little
danger in the development of harmful level of exchangeable sodium. It is inferred that the chemical composition of the groundwater
in this region is likely to have its origin from silicate weathering reactions and dissolution/precipitation processes supported
by rainfall and groundwater flow. 相似文献
484.
Manangeeswaran M Ramalingam VV Kumar K Mohan N 《Journal of environmental science and health. Part. B》2007,42(3):321-327
Serratia marcescens isolated from decaying coconut pith exhibited high lignolytic activity. Growth on indicator medium, analysis of residual indulin, and infra-red spectroscopic analysis indicated the lignolytic potential of the isolate. Ortho-Coumaric acid, ferulic acid, 2,3-dihydroxy cinnamic acid and protocatechuic acid were identified as intermediates involved in indulin degradation by S. marcescens. Qualitative confirmation and quantitative estimation of the intermediates were carried out by high performance thin layer chromatography (HPTLC). 相似文献
485.
Adsorption and degradation of sulfosulfuron in soils 总被引:3,自引:0,他引:3
Adsorption of sulfosulfuron was studied in two soils (topsoil from Alfisol and Inceptisol). The adsorption of sulfosulfuron
was greater in topsoil collected from Alfisol than in Inceptisol. The soil sorption coefficient K and the soil organic carbon sorption coefficient K
oc are the basic parameters used for describing the environmental fate of the herbicides. In topsoil the calculated K values
from Alfisol was 4.43 and in topsoil from Inceptisol was 2.00. K
c values were 6.06 in topsoil from Alfisol and 3.33 in topsoil from Inceptisol. The K
oc values were 886.36 in topsoil from Alfisol and 770.26 in topsoil from Inceptisol. Field experimental plots with no previous
history of sulfosulfuron were selected and studied the degradation of sulfosulfuron in the topsoil collected from Alfisol
and Inceptisol. The half-life of sulfosulfuron in topsoil from Alfisol: T
1− 3.97 days and T
2− 4.54 days; topsoil from Inceptisol: T
1 − 4.68 days and T
2 − 5.52 days. The degradation of sulfosulfuron followed first-order kinetics. The persistence of sulfosulfuron was found relatively
longer in the Inceptisol than in Alfisol. The combination of degradation data (t
1/2 – soil) and organic carbon based sorption (K
oc) data of herbicides have been used to assess the pesticide environmental impact in soils through Gustafson Ubiquity Score
(GUS). The GUS values were found to be 0.69 in topsoil from Alfisol and 0.83 in Inceptisol. 相似文献
486.
Soylak M Divrikli U Saracoglu S Elci L 《Environmental monitoring and assessment》2007,127(1-3):169-176
Cellulose nitrate membrane filter was used for the preconcentration-separation of Cu, Co, Cd, Pb and Cr ions. The analyte
ions were collected on the membrane filter by the aid of carmine. Then membrane filter was dissolved by using nitric acid.
The levels of the analytes in the final solutions were determined by flame atomic absorption spectrometry (FAAS). The analytical
parameters including pH, amounts of carmine, sample volumes etc. have been optimized. No influences have been observed from
the matrix ions. The detection limits for analytes were in the range of 0.08 μg/l-0.93 μg/l. The validation of the procedure
was checked by the analysis of standard reference sediment (GBW 07309). The present method has been successfully applied for
the FAAS determinations of analyte ions in real samples including black tea and magnesium salts. 相似文献
487.
The market place is considered to be an important centre of daily life of campus community. In India, as in Europe and the
USA, other forms of shopping have emerged significantly and now predominate, for instance department stores and supermarkets.
Though, it is suffered from poor waste management, but the place could be a potential source for obtaining non-conventional
energy. The present study examined the quality of market waste management of the Indian Institute of Technology Campus along
with the feasibility of biogas production from leachate generated in the waste. Solid wastes from different storage locations
of the market place were collected and analyzed. The characteristics of solid wastes were found to be degradable in nature.
The wastes, composed of 85% of vegetable origin, were placed in a container and water was added to to generate leachate. The
self-purification efficiency of leachate was also studied in the Indian environment and compared with research findings in
the USA under an identical moisture application rate. Leachate characterization was investigated both under saturated and
submerged conditions. The treatability of leachate was studied in a laboratory-scale up-flow anaerobic filter with hollow
burnt clay rings as packing media. It was observed that 4,000–6,000 mg/l would be the optimum range of inlet chemical oxygen
demand (COD) concentration for leachate treatment because of the inhibitory effect of ammonia, sulphide, volatile fatty acids
and toxic metals in high concentrations at higher strengths of leachate. The gas production rate was found to be at a maximum
at 38°C and containing 70–75% methane. From experimental data, it was revealed that 83% COD was removed with input COD concentration
of 5,475 mg/l at 2 days hydraulic retention time with biogas yield coefficients of 0.61. The present study also investigated
the removal efficiency of chloride, ammonia, sulphide and nitrate. 相似文献
488.
Goswami BK Pandey RK Goswami J Tewari DD 《Journal of environmental science and health. Part. B》2007,42(8):899-904
This investigation was undertaken to compare the percentage response of colonization and development of VA-Mycorrhiza (Glomus fasciculatum) on a number of pulse crops viz. cowpea, chickpea, soybean, pigeonpea and lentil under glasshouse conditions. Among the above-mentioned crops, pigeonpea exhibited the best performance and was selected for further studies. In this host the development and colonization percentage of G. fasciculatum was investigated under two separate substrates i. e. soil amended with FYM and karanj oilseed cake keeping a control treatment of field soil. A third treatment amended with karanj oilseed cake and farm yard manure (FYM) was also kept which responded best in terms of colonization percentage. This treatment showing improved plant health as well as integration with G. fasciculatum was selected as an ideal treatment for the management of disease complex caused by root knot nematode, Meloidogyne incognita and root wilt fungus, Fusarium udum on pigeonpea. Thus the treatment constituting FYM, karanj oilseed cake and VA-Mycorrhiza reduced the disease incidence caused by both maladies to a great extent with the most promising improvement in plant growth parameters as compared to all others. The present investigation, in addition to proposing an ideal eco-friendly treatment for the management of this disease complex also proposed an excellent medium for the proliferation of the obligate bio-protectant, G. fasciculatum. 相似文献
489.
M. H. Sayadi M. R. G. Sayyed Suyash Kumar 《Environmental monitoring and assessment》2010,162(1-4):465-473
In modern civilization, numerous anthropogenic activities release a variety of pollutants into the environment and with anomalous enrichment of heavy metals it causes surface and subsurface contamination. The aquatic sediments provide pertinent tools for the quality assessment of urban and industrial environments in large cities. The present study reveals short-term accumulative trends of heavy metals (Co, Cd, and Pb) in the sand and silt dominated riverbed sediments from Chitgar industrial area (Tehran, Iran) between the period of May 2007 and May 2008. Lead demonstrates highest concentration in residential areas, cadmium in and around industrial areas, whereas cobalt shows least variability. Geo-accumulation index implies moderately to highly polluted sediments with respect to Cd and Pb. With few exceptions, all three metals at different sampling stations display short-term increasing trends, independent of seasonal variability with urban and industrial distends along the river being the chief sources of contamination. 相似文献
490.
The present study was aimed to make an assessment of health risk due to pollution and human pathogenic bacteria associated
with the recreational and drinking water sources in twin densely populated holy Indian cities Ayodhya and Faizabad. Though
physicochemical studies revealed that the water available in the area is under recommended limits for human use, it is unsafe
on account of poor microbiological quality of surface and ground water in the region. The most probable number (MPN) test
results revealed the preponderance of ≥2,400 total coliforms (TC) (100 ml) − 1 in river, pond, dug well and kund waters. Contrary to that, 94% tube wells, 32% hand pumps and 25% piped supply water were
under safe limits having <3 TC (100 ml) − 1. The shallow depth (~40 ft), water logging and presence of septic tanks in the near vicinity are the possible reasons of
poor microbial quality of hand pump drinking water. The municipal supply water passes along sewage line where loose connections
and/or cracks in pipe lead to mixing and contamination. The significant best quality of tube well water evident from the absence
of TC could be attributed to the depth of well ≥150 ft and usually their location away from the habitation. A total of 263
bacteria from 186 water samples were isolated, and at least five genera of enteric bacteria from various water sources were
identified morphologically and biochemically as Escherichia coli, Klebsiella sp., Enterobacter sp., Shigella sp. and Salmonella sp. The serotyping of 72 E. coli and 36 Salmonella sp. revealed 51 as E. coli O157 and 20 as Salmonella sp. The presence of enteric pathogens in water sources pose threat to human health and therefore call for immediate remedial
measures. 相似文献