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641.
Manikant Tripathi Satyendra Kumar Garg 《Environmental science and pollution research international》2014,21(7):5227-5241
A native Bacillus cereus isolate has been employed, for the first time, for simultaneous decolorization, dechlorination of chloroorganics, and Cr6+ remediation from the real tannery effluent. Most of the physicochemical variables in 3:1 diluted effluent were well above the standard prescribed limits, which decreased substantially upon microbial treatment. The extent of bioremediation was better in diluted (3:1) as compared to undiluted effluent supplemented with nutrients and augmented with B. cereus isolate. Maximum growth, effluent decolorization (42.5 %), dechlorination (74.1 %), and Cr6+ remediation (34.2 %) were attained with 4.0 % (v/v) inoculum, 0.8 % glucose, and 0.2 % ammonium chloride in 3:1 diluted effluent at natural pH (8.1) within 72 h of incubation. The efficiency of bioremediation in a bioreactor was higher as compared to a flask trial during 72 h of incubation: decolorization (47.9 %) was enhanced by 5.4 %, dechlorination (77.4 %) by 3.3 %, and Cr6+ removal (41.7 %) by 7.5 % at an initial color of 286 Pt-Co units and initial concentration of 62 mg chloride ions and 108 mg l?1 Cr6+. Immobilized biomass of Pseudomonas putida and B. cereus coculture enhanced the extent of Cr6+ remediation (51.9 %) by 10.2 % compared to the bioreactor trial. Chromate reductase activity and reduced Cr directly correlated and were mainly associated with soluble fraction of B. cereus plus effluent natural microflora. The GC-MS analyses revealed the formation of metabolites such as acetic acid and 2-butenoic acid in bacterially treated effluent. The supplementation of nutrients along with B. cereus augmentation is required for efficient effluent bioremediation. 相似文献
642.
Triclosan in Fresh Water Fish Gibelion Catla from the Kaveri River,India, and Its Consumption Risk Assessment 总被引:1,自引:0,他引:1
Govindaraj Shanmugam Karthik Ramasamy Krishna Kumar Selvaraj Srimurali Sampath 《Environmental Forensics》2014,15(3):207-212
Triclosan is a common antimicrobial agent that is found in significant levels in the aquatic environment and may elicit effects on aquatic organisms through unexpected modes of action. In this study, triclosan was quantified in fish from the Kaveri River, India, by using the gas chromatography and mass spectrometry technique and it was found in the range of 0.73–50 ng/g wet weight (ww). The mean bioaccumulation factor based on water (BAFw 820) and sediment (BAFs 2.12) in the Kaveri River showed that triclosan is accumulative in fish, and reflects its feeding behavior. The bioaccumulation indicates triclosan's persistence or prevalence throughout the river stretch. Human risk assessment through dietary intake demonstrated that the triclosan exposure is five orders of magnitude lower than the acceptable daily intake (50 μg/kg bw) and US EPA reference dose (300 μg/kg bw/day). This investigation is the first to report the bioaccumulation of triclosan in freshwater fish from India. Further, the results indicate that this fish acts as a biomarker of exposure for triclosan and thus shall be used to report triclosan pollution in the future. 相似文献
643.
644.
Karanja oil, containing 6.2% free fatty acids (FFAs), was considered for biodiesel production using a single-step solid-phase acid catalyzed process. Different types of zeolites and Amberlyst15 catalysts were tested and biodiesel was produced. Under similar conditions, the highest biodiesel yield was achieved using an Amberlyst15 catalyst, which contained 3–5% of moisture. The effects of operating parameters of the reaction such as reaction temperature, catalyst amount, and methanol-to-oil ratio were studied. An increase of methanol:oil ratio revealed a non-monotonic increase in biodiesel yields. Similar non-monotonic behavior was observed when Jatropha oil was used. Leaching and catalyst reusability were also considered. No significant effects of leaching were observed and catalyst reusability appeared to be affected by methanol interactions. The presence of a co-solvent, Tetrahydrofuran (THF), increased the biodiesel yield. Furthermore, an optimum amount of THF (THF:methanol volume ratio of 1:2) gave rise to the highest biodiesel yield. A biodiesel yield of 93% was achieved at 120 °C using a single-step process with Amberlyst15 as a catalyst, THF as a co-solvent, and a methanol:oil ratio of 30:1. 相似文献
645.
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
646.
Hydrogeochemical studies were carried out in the Penna–Chitravathi river basins to identify and delineate the important geochemical processes which were responsible for the evolution of chemical composition of groundwater. The area is underlain by peninsular gneissic complex of Archaean age, Proterozoic meta-sediments, and strip of river alluvium. Groundwater samples were collected covering all the major hydrogeological environs in pre- and post-monsoon seasons. The samples were analyzed for major constituents such as Ca2?+?, Mg2?+?, Na?+?, K?+?, CO3 ???, HCO3 ???, Cl???, SO2 ???4, NO3 ???, and F???. The groundwater in general is of Na?+?–Cl???, Na?+?–HCO3 ???, Ca2?+?–Mg2?+?–HCO3 ???, and Ca2?+?–Mg2?+?–Cl??? types. Na?+? among cations and Cl??? and/or HCO3 ??? among anions dominate the water; Na?+? and Ca2?+? are in the transitional state with Na?+? replacing Ca2?+? and HCO3 ??? Cl??? due to physiochemical changes in the aquifer and water–rock interactions. The Ca2?+?–Mg2?+?–Cl??? HCO3 ??? type water in one third samples suggest that ion exchange and dissolution processes are responsible for its origin. Change in storage of aquifer in a season does not influence the major geochemical makeup of groundwater. Gibbs plots indicate that the evolution of water chemistry is influenced by water–rock interaction followed by evapotranspiration process. The aquifer material mineralogy together with semiarid climate, poor drainage system, and low precipitation factors played major role in controlling groundwater quality of the area. 相似文献
647.
Furquan Ahmad Ansari Altaf Husain Khan Devendra Kumar Patel Huma Siddiqui Shachi Sharma Mohammad Ashquin Iqbal Ahmad 《Environmental monitoring and assessment》2010,170(1-4):491-497
In order to evaluate the exposure of the northern India rural population to polyaromatic hydrocarbon (PAH) inhalation, indoor pollution was assessed by collecting and analyzing the respirable particulate matter PM2.5 and PM10 in several homes of the village Bhithauli near Lucknow, UP. The home selection was determined by a survey. Given the nature of biomass used for cooking, homes were divided into two groups, one using all kinds of biomass and the second type using plant materials only. Indoor mean concentrations of PM2.5 and associated PAHs during cooking ranged from 1.19 ± 0.29 to 2.38 ± 0.35 and 6.21 ± 1.54 to 12.43 ± 1.15 μg/m3, respectively. Similarly, PM10 and total PAHs were in the range of 3.95 ± 1.21 to 8.81 ± 0.78 and 7.75 ± 1.42 to 15.77 ± 1.05 μg/m3, respectively. The pollutant levels during cooking were significantly higher compared to the noncooking period. The study confirmed that indoor pollution depends on the kind of biomass fuel used for cooking. 相似文献
648.
Raj Kumar Singh Manoj Datta Arvind Kumar Nema 《Environmental Modeling and Assessment》2010,15(6):549-567
In developing countries, several old municipal solid waste dumps (unlined landfills) exist adjacent to large cities, releasing
contaminants to the underlying aquifer, thus posing the hazard of groundwater contamination. These uncontrolled waste dumps
need to be prioritized in terms of the groundwater contamination hazard posed by them, so that necessary control and remedial
measures can be undertaken in a phased manner. This paper presents a time-dependent system for evaluating groundwater contamination
hazard rating of municipal solid waste dumps. The system is based on source–pathway–receptor relationships and evaluates the
relative value of hazard posed by a site over its entire leaching life, on a scale of 0–1,000. The system parameters have
been selected based on literature and expert opinions. The Delphi technique is used to derive the relative importance weights
of the system parameters. The proposed system is compared with six selected existing hazard rating systems. The comparison,
made by way of score range analysis, shows that the proposed system exhibits a much wider range of hazard scores for various
scenarios of site conditions, and hence the proposed system is more sensitive to varied site conditions. The application of
different systems to six municipal solid waste dumps located in four cities of India shows that, whereas the existing systems
individually produce clustered scores and return the same rank to more than one site, the proposed system produces significantly
varying scores and return different ranks to different sites. This demonstrates that the proposed system improves decision
making and makes a better basis for prioritization of municipal solid waste dumps for adopting control and remedial measures. 相似文献
649.
Munmun Chakarvorty Jayanta Kumar Pati Shiva Kumar Patil Swati Shukla Ambalika Niyogi Arun Kumar Saraf 《Environmental monitoring and assessment》2014,186(5):2965-2978
The winter fog in India is a recurrent phenomenon for more than a decade now affecting the entire Himalayan and sub-Himalayan regions covering an area of nearly 500,000 km2. Every winter (December–January), the air and surface transports in cities of northern India (Amritsar, New Delhi, Agra, Gwalior, Kanpur, Lucknow, and Allahabad) are severely disrupted with visibility reduced to <50 m at times. Since dust particles are known to act as nuclei for the fog formation, this study is aimed to carry out physicochemical characterization of the dust particulates accumulated during a protracted fog period from one of the severely fog affected cities of north India (Allahabad; 25°27′33.40″N–81°52′45.47″E). The dust-loaded tree leaves belonging to Ficus bengalensis and Ficus religiosa from 50 different locations between January 24 and 31, 2010 are sampled and characterized. The mass of dust, color, grain shape, size, phase constituents, and mineral magnetic parameters, such as magnetic susceptibility, SIRM, χ fd%, and S-ratio, show minor variation and the regional influence outweighs local anthropogenic contributions. The dust compositions show fractionated rare earth element pattern with a pronounced negative Eu anomaly similar to upper continental crust and further suggesting their derivation from sources located in parts of north and central India. 相似文献
650.
Vibudh P. Kesari Amod Kumar Parimal K. Khan 《Environmental monitoring and assessment》2014,186(5):3115-3121
The ubiquitous presence of arsenic (a toxic metalloid) in our environment, particularly in our drinking water, is a serious health hazard of global concern. The present work deals with the assessment of arsenic toxicity through the analysis of induced sperm impairments in sperm head morphology and sperm count in mice at low exposures compared to the magnitude of response at high exposure levels. The animals were exposed to four doses of arsenic, ranging from lowest dose of 0.3 μg kg?1 day?1 (the human reference dose) to higher dose of 30 μg kg?1 day?1 for 15 consecutive days. The epididymal sperms were harvested after one spermatogenic cycle on the 36th day and were scored for the presence of any abnormality in their head morphology as well as changes in their count. Exposure to arsenic significantly induced, in a dose-dependent manner, increases in the frequency of sperms with abnormal head morphology from 5.12 % in control to 9.23 % in lowest dose group and 23.02 % in highest dose group. In contrast, the mean sperm counts in the epididymal wash were decreased from 6.05 million per milliliter in the control to 4.95 million per milliliter in the lowest dose group and 3.07 million in the highest dose group. The analysis of sperm impairments in mice was, therefore, found to be a highly sensitive assay to assess arsenic toxicity, exhibiting a marked male reprotoxic effect of arsenic even at its low exposure levels including the human reference dose. 相似文献