首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   259篇
  免费   2篇
  国内免费   3篇
安全科学   3篇
废物处理   13篇
环保管理   24篇
综合类   29篇
基础理论   45篇
污染及防治   97篇
评价与监测   37篇
社会与环境   15篇
灾害及防治   1篇
  2023年   9篇
  2022年   12篇
  2021年   9篇
  2020年   1篇
  2019年   3篇
  2018年   3篇
  2017年   10篇
  2016年   8篇
  2015年   6篇
  2014年   14篇
  2013年   35篇
  2012年   13篇
  2011年   14篇
  2010年   10篇
  2009年   5篇
  2008年   16篇
  2007年   14篇
  2006年   12篇
  2005年   10篇
  2004年   10篇
  2003年   4篇
  2002年   4篇
  2001年   6篇
  1999年   2篇
  1997年   1篇
  1996年   3篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1991年   1篇
  1990年   2篇
  1987年   1篇
  1985年   1篇
  1984年   2篇
  1982年   4篇
  1978年   1篇
  1976年   1篇
  1969年   1篇
  1968年   1篇
  1967年   1篇
  1966年   3篇
  1964年   3篇
  1963年   4篇
  1962年   1篇
排序方式: 共有264条查询结果,搜索用时 15 毫秒
151.
Occurrence of phthalic acid esters in Gomti River Sediment, India   总被引:2,自引:0,他引:2  
Cadmium and lead are important environmental pollutants with high toxicity to animals and human. Soils, though have considerable metal immobilizing capability, can contaminate food chain via plants grown upon them when their built-up occurs to a large extent. Present experiment was carried out with the objective of quantifying the limits of Pb and Cd loading in soil for the purpose of preventing food chain contamination beyond background concentration levels. Two separate sets of pot experiment were carried out for these two heavy metals with graded levels of application doses of Pb at 0.4–150 mg/kg and Cd at 0.02–20 mg/kg to an acidic light textured alluvial soil. Spinach crop was grown for 50 days on these treated soils after a stabilization period of 2 months. Upper limit of background concentration levels (C ul) of these metals were calculated through statistical approach from the heavy metals concentration values in leaves of spinach crop grown in farmers’ fields. Lead and Cd concentration limits in soil were calculated by dividing C ul with uptake response slope obtained from the pot experiment. Cumulative loading limits (concentration limits in soil minus contents in uncontaminated soil) for the experimental soil were estimated to be 170 kg Pb/ha and 0.8 kg Cd/ha. Based on certain assumptions on application rate and computed cumulative loading limit values, maximum permissible Pb and Cd concentration values in municipal solid waste (MSW) compost were proposed as 170 mg Pb/kg and 0.8 mg Cd/kg, respectively. In view of these limiting values, about 56% and 47% of the MSW compost samples from different cities are found to contain Pb and Cd in the safe range.  相似文献   
152.
The present study showed that irrigation of soil with different effluent concentrations (10, 25, 50, 75, and 100 %) of distillery effluent (DE) for 60 days resulted in significant (P?<?0.001) changes in moisture content; electrical conductivity (EC), pH, chlorides (Cl?), total organic carbon (TOC), exchangeable sodium (Na+), available potassium (K+), calcium (Ca2+), magnesium (Mg2+), iron (Fe2+), total Kjeldahl nitrogen (TKN), available phosphorus (P), and sulfate (SO4 2?) of soil. The non-significant (P?>?0.05) changes were observed for water-holding capacity and bulk density of the soil. Among various concentrations of DE irrigation, irrigation with 100 % effluent concentration increased moisture content, (24.85 %), EC (77.88 %), Cl? (285.95 %), TOC (3,171.42 %), exchangeable Na+ (241.04 %), available K+ (52.49 %), Ca2+ (990.37 %), Mg2+ (1,751.72 %), TKN (1,417.00 %), available P (305.00 %), and SO4 2? (75.32 %) in the soil and decreased pH (?20.22 %). The more stimulation in agronomical parameters such as shoot length, root length, number of leaves, flowers, pods, dry weight, fresh weight, chlorophyll content, leaf area index, and crop yield of A. esculentus were observed to be inversely proportional to the concentration of effluent water, with the best results being obtained at a dilution of 25 % of DE concentration.  相似文献   
153.
In the peri-urban areas of central India, sewage water is a valuable resource for agricultural production. In this study, impact of domestic sewage water irrigation for 5 years on Vertisol with no previous history of sewage irrigation was investigated in an ongoing field experiment at Bhopal (India) under subtropical monsoon type climate. The wheat (Triticum aestivum) crop was grown during post-rainy winter season with 30 cm of irrigation (groundwater or sewage water) and four nutrient treatments (T1, 0; T2, 100%; T3, 50%; and T4, 50% of general recommended doses of NPK + FYM at 10 Mg/ha). Results showed that sewage irrigation of about 150 cm over a period of 5 years resulted significant increases in salinity as well as available fractions of N, P, K, and micronutrients, viz., Zn, Fe, and Mn in soils. Carbon and phosphorus applied through sewage water were accumulated more in subsoil layer compared to topmost plough layer. Soil microbiological activity, as indicated by soil respiration, microbial biomass C, as well as dehydrogenase enzyme activity was higher in sewage water-irrigated soils. There was also significant increase in fungal and actinomycetes as well as total coliform population in such soils. Nutrients supplied through sewage water were not able to raise the productivity of wheat to the level that obtained through fertilizers at the recommended level which indicated that additional nutrients through fertilizers are required to obtain higher productivity of wheat under sewage farming. Protein and Zn content in wheat grains were more when the crop was grown with sewage irrigation. Overall results show that except for increase in coliform population, short duration (5 years) of municipal sewage water irrigation did not have any appreciable harmful effect on soil quality as well as crop productivity; rather, it proved beneficial in improving soil fertility, wheat productivity, and produce quality.  相似文献   
154.
Use of indifference curves, defined as functionality between development index and pollution load to evaluate environmental impact, is proposed. Existing Battelle environmental evaluation methodology is subjective in its approach. The use of indifference curves lends a more objective approach to environment assessment methodology. The extent of environmental damage we are prepared to accept, for a development, can be explained by Willingness to Pay and Willingness to Accept approach. The application of proposed approach has been demonstrated taking an example of Power plant set up in forest area. The curves clearly show that cost of EMP considering mitigation of ecological damage is higher than the EMP mitigating impacts of air and water pollution only. The example stresses the need for willingness to accept along with willingness to pay.  相似文献   
155.
Source-contribution assessment of ambient NO2 concentration was performed at Pantnagar, India through simulation of two urban mathematical dispersive models namely Gaussian Finite Line Source Model (GFLSM) and Industrial Source Complex Model (ISCST-3) and model performances were evaluated. Principal approaches were development of comprehensive emission inventory, monitoring of traffic density and regional air quality and conclusively simulation of urban dispersive models. Initially, 18 industries were found responsible for emission of 39.11 kg/h of NO2 through 43 elevated stacks. Further, vehicular emission potential in terms of NO2 was computed as 7.1 kg/h. Air quality monitoring delineates an annual average NO2 concentration of 32.6 μg/m3. Finally, GFLSM and ISCST-3 were simulated in conjunction with developed emission inventories and existing meteorological conditions. Models simulation indicated that contribution of NO2 from industrial and vehicular source was in a range of 45-70% and 9-39%, respectively. Further, statistical analysis revealed satisfactory model performance with an aggregate accuracy of 61.9%.  相似文献   
156.

Purpose

Electroplating industries are the main sources of heavy metals, chromium, nickel, lead, zinc, cadmium and copper. The highest concentrations of chromium (VI) in the effluent cause a direct hazards to human and animals. Therefore, there is a need of an effective and affordable biotechnological solution for removal of chromium from electroplating effluent.

Methods

Bacterial strains were isolated from electroplating effluent to find out higher tolerant isolate against chromate. The isolate was identified by 16S rDNA sequence analysis. Absorbed chromium level of bacterium was determined by inductively coupled plasma-atomic emission spectrometer (ICP-AES), atomic absorption spectrophotometer (AAS), scanning electron microscope (SEM), transmission electron microscope (TEM) and energy dispersive X-ray analysis (EDX). Removal of metals by bacterium from the electroplating effluent eventually led to the detoxification of effluent confirmed by MTT assay. Conformational changes of functional groups of bacterial cell surface were studied through Fourier transform infrared spectroscopy.

Results

The chromate tolerant isolate was identified as Bacillus cereus. Bacterium has potency to remove more than 75% of chromium as measured by ICP-AES and AAS. The study indicated the accumulation of chromium (VI) on bacterial cell surface which was confirmed by the SEM-EDX and TEM analysis. The biosorption of metals from the electroplating effluent eventually led to the detoxification of effluent. The increased survivability of Huh7 cells cultured with treated effluent also confirmed the detoxification as examined by MTT assay.

Conclusion

Isolated strain B. cereus was able to remove and detoxify chromium (VI). It would be an efficient tool of the biotechnological approach in mitigating the heavy metal pollutants.  相似文献   
157.
Fluoride concentration and other parameters in groundwater from 261 villages in Tehsil Kheragarh of District Agra were assessed and attempts were made to observe the relationship between fluoride and other water quality parameters. Of 658 groundwater samples (collected from separate sources) analysed for fluoride, 27% were in the range of 0–1.0 mg/L, 25% in 1.0–1.5 mg/L, 32% in1.5–3.0 mg/L and 16% above 3.0 mg/L. The highest fluoride concentration recorded was 12.80 mg/L. Significant correlation of fluoride with pH, alkalinity, Na, SiO2 and PO4 were observed. Factor analysis was also attempted in order to identify the contributing sources.  相似文献   
158.
Srivastava SK 《Disasters》2009,33(1):58-81
The right mix of policy, institutional arrangements and use of technology provides the framework for a country's approach to disaster mitigation. Worldwide, there has been a shift away from a strictly 'top-down' approach relying on government alone, to a combination of 'top-down' and 'bottom-up' approaches. The aim is to enhance the indigenous coping mechanisms of vulnerable communities; draw on their cooperative spirit and energy; and empower them through appropriate information and contextual knowledge to mitigate natural disasters. In light of this, the paper examines India's use of space technology in its disaster management efforts. Poverty alleviation and disaster management are almost inseparable in many parts of the country, as vulnerability to natural disasters is closely aligned with poverty. Addressing these issues together requires integrated knowledge systems. The paper examines how knowledge inputs from space technology have strengthened the national resolve to combat natural disasters in conjunction with alleviating rural poverty.  相似文献   
159.
Conservation practitioners require strata specific, seasonal species densities for habitat management. Herein, we use stratified distance sampling in Kanha Tiger Reserve (KTR) with 200 spatial transects and an effort of 1200 km walk in the year 2013. Analysis was done to access (a) impact of human use and (b) effect of habitat and season on ungulate densities in KTR. While a single detection function for each species was used for estimating density within human-restricted core and multiple use buffer of KTR, species-specific seasonal detections were modelled for each habitat. Ungulate biomass was 4.8 times higher in the core area compared with the buffer zone. The core supported a herbivore density and biomass of 50 ± 4.80/km2 and 26,806 ± 2573 kg/km2, respectively. Chital were found to be most abundant, having a density of 30.1 ± 4.34/km2 and contributing 33 % of the biomass with a habitat preference for grasslands (106 ± 39/km2) in summer and winter. Sambar had highest density (15.4 ± 3.34/km2) in bamboo-mixed habitat, in both seasons. Gaur contributed 39 % of the ungulate biomass and showed a seasonal shift in density from sal forests (9.65 ± 3.55/km2) in summer to miscellaneous forests (8.13 ± 1.94/km2) in winter. Barasingha were restricted to grasslands with similar summer and winter densities of 1.56 ± 0.76/km2. Chousingha were rare (0.1 ± 0.04/km2), found mostly in miscellaneous forests and plateau grasslands. Grassland and bamboo-mixed forests supported 58 % of the total ungulate biomass. Management for an optimal habitat mosaic that maintains ungulate diversity, addresses the specific needs of endangered species and maximizes ungulate biomass is recommended.  相似文献   
160.
Linnér BO  Pahuja N 《Ambio》2012,41(Z1):56-67
This article examines key issues in operationalizing a registry of nationally appropriate mitigation actions (NAMAs) undertaken by developing countries party to the United Nations framework convention on climate change. It analyzes goals, outcomes, and institutional prerequisites underlying various proposals to determine how a NAMA mechanism could work in international climate cooperation. The different proposals for how NAMA shall be designed relate to three basic effort-sharing arrangements in a future climate regime: binding commitments for all Parties, purely voluntary commitments for all, and legally binding commitments for Annex I countries but voluntary ones for others. We conclude that a NAMA registry could be designed so as initially to suit all three types of effort-sharing regimes. The article identifies three areas of potential common ground in a registry irrespective of effort-sharing type: the principle of common but differentiated responsibilities, the sustainable development objectives of the Convention, and the need for a systemic transition toward low-carbon energy technologies.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号