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181.
西昌邛海水质现状调查分析 总被引:3,自引:0,他引:3
四川西昌的邛海水体中浮游植物群体组成以硅藻、绿藻及鼓藻为主,据1986~1991年连续监测结果表明,邛海水质总体处于贫营养状况,仅局部有富营养性藻类出现。 相似文献
182.
A. Datta K. S. Rao S. C. Santra T. K. Mandal T. K. Adhya 《Mitigation and Adaptation Strategies for Global Change》2011,16(5):597-615
Recent market slump in rice, less rainfall during monsoon, high temperature and scarcity of water during dry season leads
to lower grain yield and less profit from rice cultivation in India. Farmers’ grow upland crops like chickpea (Cicer arietinum), greengram (Vigna radiate), mustard (Brassica nigra), corn (Zea maize), pigeonpea (Cajanus cajan), potato (Solanum tuberosum), sunflower (Helianthus annuus) etc. along with rice (Oryza sativa) during the dry season. However, knowledge of greenhouse gas (GHG) emission from these rice based cropping systems is very
limited. In the present study four rice based cropping systems was studied along with rice-rice rotation system as control
in respect of GHG emission, yield potential and economic feasibility. Conventional plantation and fertilizer application methodology
was followed for each crop. Methane (CH4) and nitrous oxide (N2O) flux from field plots were studied with conventional closed chamber method using gas chromatograph. CH4 flux was recorded highest from rice-rice rotation plots (304.25 kg ha−1). N2O flux was recorded 1.02 kg ha−1 from rice-rice rotation system during wet season. However, during wet season, higher N2O flux (1.93 kg ha−1) was recorded from rice-potato-sesame rotation plots. Annual N2O flux was also recorded significantly low (3.42 kg ha−1) from rice-rice rotation plots and high (6.19 kg ha−1) from rice-chickpea-greengram rotation plots. Significantly lower annual grain yield was recorded from rice-rice rotation
plots (9.25 Mg ha−1) whereas it was 18.84 Mg rice eq ha−1 from rice-potato-sesame rotation system. The global warming potential (GWP) of rice-rice rotation system was recorded significantly
high (8.62 Mg CO2 ha−1) compare to plots with different rice based cropping systems. Computing all C-emission from cradle-to-grave, highest total
C-cost was recorded from the rice-rice rotation system ($62.00 ha−1). We have made an attempt to calculate the C-credit of different rice based cropping systems by considering the difference
of C-cost with control. The study suggests that the rice-potato-sesame is most sustainable among different cropping system
studied in terms of economic profit ($62.00 ha−1). We have made an attempt to calculate the C-credit of different rice based cropping systems by considering the difference
of C-cost with control. The study suggests that the rice-potato-sesame is most sustainable among different cropping system
studied in terms of economic profit (1248.21 ha−1) and C-credit ($38.60 ha−1). The result of the study may be limited to the study region; however, the study has potential use in respect to the development
of agriculture practice for adaptation to climate change. 相似文献
183.
184.
185.
Ku-Fan Chen Chih-Ming Kao Chiu-Wen Chen Rao Y. Surampalli Mu-Sheng Lee 《环境科学学报(英文版)》2010,22(6):864-871
In the first phase of this study, the e ectiveness of intrinsic bioremediation on the containment of petroleum hydrocarbons was
evaluated at a gasoline spill site. Evidences of the occurrence of intrinsic bioremediation within the BTEX (benzene, toluene,
ethylbenzene, and xylenes) plume included (1) decreased BTEX concentrations; (2) depletion of dissolved oxygen (DO), nitrate,
and sulfate; (3) production of dissolved ferrous iron, methane, and CO2; (4) deceased pH and redox potential; and (5) increased
methanogens, total heterotrophs, and total anaerobes, especially within the highly contaminated areas. In the second phase of this study,
enhanced aerobic bioremediation process was applied at site to enhance the BTEX decay rates. Air was injected into the subsurface
near the mid-plume area to biostimulate the naturally occurring microorganisms for BTEX biodegradation. Field results showed that
enhanced bioremediation process caused the change of BTEX removal mechanisms from anaerobic biodegradation inside the plume
to aerobic biodegradation. This variation could be confirmed by the following field observations inside the plume due to the enhanced
aerobic bioremediation process: (1) increased in DO, CO2, redox potential, nitrate, and sulfate, (2) decreased in dissolved ferrous iron,
sulfide, and methane, (3) increased total heterotrophs and decreased total anaerobes. Field results also showed that the percentage
of total BTEX removal increased from 92% to 99%, and the calculated total BTEX first-order natural attenuation rates increased
from 0.0092% to 0.0188% per day, respectively, after the application of enhanced bioremediation system from the spill area to the
downgradient area (located approximately 300 m from the source area). 相似文献
186.
Dephenolization and detoxification of olive-mill wastewater (OMW) by purified biotic and abiotic oxidative catalysts 总被引:1,自引:0,他引:1
The capability of two oxidative catalysts, a laccase from Rhus vernicifera and birnessite, a manganese oxide, in the dephenolization and detoxification of two olive-mill wastewater (OMW) samples, C1 and C2, differing for complexity and composition, was evaluated. OMW phenolic extracts (EC1 and EC2) and mono-substrate solutions of phenols mostly present in OMW samples were also tested. Birnessite was more effective than laccase in removing the phenolic content from mono-substrate solutions (more than 70% of each initial phenolic concentration) and of either OMW samples or EC1 and EC2 extracts. For instance, 60% of the total phenolic content of EC1 was removed after 48-h treatment with 5 mg mL(-1) birnessite and the efficiency was lower as greater was the complexity of the OMW sample (only 17% removal from EC2 over the same time span). Phytotoxicity tests with Lepidium sativum and Lycopersicon esculentum seeds and antibacterial toxicity tests with Bacillus megaterium were performed on crude OMW samples and their extract and exhausted fractions before and after the catalytic treatment. Results demonstrated that (a) monomeric phenols were certainly but not exclusively responsible of OMW phytotoxicity, whereas their removal led to a quite complete elimination of the toxicity toward bacterial growth; (b) other components not removable by the oxidative catalysts very likely contribute to OMW phytotoxicity; and (c) the choice of the vegetal species to use in toxicity tests might be crucial for correct and easily interpretable results. Overall the results provided useful information on the possible use of oxidative catalysts for the efficient treatment of complex aqueous wastes such as those deriving from olive industry. 相似文献
187.
Integration of traditional and innovative characterization techniques for flux-based assessment of Dense Non-aqueous Phase Liquid (DNAPL) sites 总被引:1,自引:0,他引:1
Nandita B. Basu P. Suresh C. Rao Irene C. Poyer Subhas Nandy Megharaj Mallavarapu Ravi Naidu Greg B. Davis Bradley M. Patterson Michael D. Annable Kirk Hatfield 《Journal of contaminant hydrology》2009,105(3-4):161-172
Key attributes of the source zone and the expanding dissolved plume at a trichloroethene (TCE) site in Australia were evaluated using trends in groundwater monitoring data along with data from on-line volatile organic compound (VOC) samplers and passive flux meters (PFMs) deployed in selected wells. These data indicate that: (1) residual TCE source mass in the saturated zone, estimated using two innovative techniques, is small ( 10 kg), which is also reflected in small source mass discharge ( 3 g/day); (2) the plume is disconnecting, based on TCE concentration contours and TCE fluxes in wells along a longitudinal transect; (3) there is minimal biodegradation, based on TCE mass discharge of 6 g/day at a plume control plane 175 m from source, which is also consistent with aerobic geochemical conditions observed in the plume; and (4) residual TCE in the vadose zone provides episodic inputs of TCE mass to the plume during infiltration/recharge events. TCE flux data also suggest that the small residual TCE source mass is present in the low-permeability zones, thus making source treatment difficult. Our analysis, based on a synthesis of the archived data and new data, suggests that source treatment is unwarranted, and that containment of the large TCE plume ( 1.2 km long, 0.3 km wide; 17 m deep; 2000–2500 kg TCE mass) or institutional controls, along with a long-term flux monitoring program, might be necessary. The flux-based site management approach outlined in this paper provides a novel way of looking beyond the complexities of groundwater contamination in heterogeneous domains, to make intelligent and informed site decisions based on strategic measurement of the appropriate metrics. 相似文献
188.
Priyanka Bihari A. K. Nayak Priyanka Gautam B. Lal M. Shahid R. Raja R. Tripathi P. Bhattacharyya B. B. Panda S. Mohanty K. S. Rao 《Environmental monitoring and assessment》2015,187(5):296
Integrated rice–fish culture, an age-old farming system, is a technology which could produce rice and fish sustainably at a time by optimizing scarce resource use through complementary use of land and water. An understanding of microbial processes is important for the management of farming systems as soil microbes are the living part of soil organic matter and play critical roles in soil C and N cycling and ecosystem functioning of farming system. Rice-based integrated farming system model for small and marginal farmers was established in 2001 at Central Rice Research Institute, Cuttack, Odisha. The different enterprises of farming system were rice–fish, fish–fingerlings, fruits, vegetables, rice–fish refuge, and agroforestry. This study was conducted with the objective to assess the soil physicochemical properties, microbial population, carbon and nitrogen fractions, soil enzymatic activity, and productivity of different enterprises. The effect of enterprises induced significant changes in the chemical composition and organic matter which in turn influenced the activities of enzymes (urease, acid, and alkaline phosphatase) involved in the C, N, and P cycles. The different enterprises of long-term rice-based farming system caused significant variations in nutrient content of soil, which was higher in rice–fish refuge followed by rice–fish enterprise. Highest microbial populations and enzymatic properties were recorded in rice–fish refuge system because of waterlogging and reduced condition prolonged in this system leading to less decomposition of organic matter. The maximum alkaline phosphatase, urease, and FDA were observed in rice–fish enterprise. However, highest acid phosphatase and dehydrogenase activity were obtained in vegetable enterprise and fish–fingerlings enterprise, respectively. 相似文献
189.
M. K. Sharma C. K. Jain G. Tamma Rao V. V. S. Gurunadha Rao 《Environmental monitoring and assessment》2015,187(5):295
Migration pattern of organochloro pesticide lindane has been studied in groundwater of metropolitan city Vadodara. Groundwater flow was simulated using the groundwater flow model constructed up to a depth of 60 m considering a three-layer structure with grid size of 40?×?40?×?40 m3. The general groundwater flow direction is from northeast to south and southwest. The river Vishwamitri and river Jambua form natural hydrologic boundary. The constant head in the north and south end of the study area is taken as another boundary condition in the model. The hydraulic head distribution in the multilayer aquifer has been computed from the visual MODFLOW groundwater flow model. TDS has been computed though MT3D mass transport model starting with a background concentration of 500 mg/l and using a porosity value of 0.3. Simulated TDS values from the model matches well with the observed data. Model MT3D was run for lindane pesticide with a background concentration of 0.5?μg/l. The predictions of the mass transport model for next 50 years indicate that advancement of containment of plume size in the aquifer system both spatially and depth wise as a result of increasing level of pesticide in river Vishwamitri. The restoration of the aquifer system may take a very long time as seen from slow improvement in the groundwater quality from the predicted scenarios, thereby, indicating alarming situation of groundwater quality deterioration in different layers. It is recommended that all the industries operating in the region should install efficient effluent treatment plants to abate the pollution problem. 相似文献
190.
确定卫生防护距离应注意的问题 总被引:10,自引:0,他引:10
饶示欣 《石油化工环境保护》1999,(4):42-43
本文总结了石化行业卫生防护距离标准编制和环境影响评价工作中的经验,对确定卫生防护距离时应注意的一些问题进行了探讨,并提出了一种新的确定石化装置废气无组织排放量的方法。 相似文献