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341.
A. Ramachandra Rao Srinivasa G. Rao R. L. Kashyap 《Journal of the American Water Resources Association》1985,21(5):757-770
Stochastic models fitted to hydrologic data of different time scales are interrelated because the higher time scale data (aggregated data) are derived from those of lower time scale. Relationships between the statistical properties and parameters of models of aggregated data and of original data are examined in this paper. It is also shown that the aggregated data can be more accurately predicted by using a valid model of the original data than by using a valid model of the aggregated data. This property is particularly important in forecasting annual values because only a few annual values are usually available and the resulting forecasts are relatively inaccurate if models based only on annual data are used. The relationships and forecasting equations are developed for general aggregation time and can be used for hourly and daily, daily and monthly or monthly and yearly data. The method is illustrated by using monthly and yearly streamflow data. The results indicate that various statistical characteristics and parameters of the model of annual data can be accurately estimated by using the monthly data and forecasts of annual data by using monthly models have smaller one step ahead mean square error than those obtained by using annual data models. 相似文献
342.
343.
HSE项目管理体系中环境保护专业的作用 总被引:1,自引:0,他引:1
饶未欣 《石油化工环境保护》2003,26(3):1-5
在对比国内建设项目环保管理体系和HSE环保管理体系的基础上,总结了PMC项目环保管理工作的经验,对HSE项目管理运作模式中环保专业的职能和作用进行了一定程度的探讨。 相似文献
344.
Anirban Akhand Abhra Chanda Sachinandan Dutta Sudip Manna Pranabes Sanyal Sugata Hazra K. H. Rao V. K. Dadhwal 《Environmental monitoring and assessment》2013,185(8):6505-6515
A comprehensive attempt has been made to evaluate the diurnal and spatial pattern of CO2 exchange between the atmosphere and water along the estuarine track of Indian Sundarbans during the two summer months, April and May, 2011. Rigorous field observations were carried out which included the hourly measurements of total alkalinity, pH, fugacity of CO2 in ambient air and water surface, dissolved oxygen, and chlorophyll a. The estuarine water was found rich in total alkalinity and was oversaturated with CO2 throughout the diurnal cycle in the two stations situated at the inner and middle estuary, respectively, whereas an entirely reverse situation was observed in the outer fringes. The fugacity of CO2 in water ranged from 152 to 657 μatm during the study period. The percentage of over-saturation in inner and middle estuary varied from 103 to 168 and 103 to 176 %, respectively, whereas the degree of under-saturation in the outer estuary lied between 40 and 99 %. Chlorophyll a concentrations were found higher in the outer estuary (12.3?±?2.2 mg?m?3) compared to the middle (6.4?±?0.6 mg?m?3) and inner parts (1.6?±?0.2 mg?m?3), followed by a similar decreasing pattern in nutrient availability from the outer to inner estuary. The sampling stations situated at the inner and middle estuary acted as a net source of 29.69 and 23.62 mg?CO2?m?2 day?1, respectively, whereas the outer station behaved as a net sink of ?33.37 mg?CO2 m?2 day?1. The study of primary production and community respiration further supports the heterotrophic nature of the estuary in the inner region while the outer periphery was marked by dominant autotrophic character. These contrasting results are in parity with the source characters of many inner estuaries and sinking characters of the outer estuaries situated at the distal continental shelf areas. 相似文献
345.
Assessment of nitrate contamination due to groundwater pollution in north eastern part of Anantapur District, A.P. India 总被引:1,自引:0,他引:1
Reddy AG Niranjan Kumar K Subba Rao D Sambashiva Rao S 《Environmental monitoring and assessment》2009,148(1-4):463-476
The north eastern part of Anantapur district is in the state of Andhra Pradesh, India, is significant as it is covered by varied geological formations and has different land use and irrigation practices. Though ground water is the major drinking water source, deterioration in its quality is going unchecked. In such agro-economy based rural areas, the nitrate contamination is rampant and much attention has not been drawn towards this anthropogenic pollution. In the study area ground water samples from different hydrogeological set-up have been collected during the pre and post monsoon seasons and analysed for the major ions such as Ca, Mg, Na, K, CO(3), HCO(3), Cl, SO(4), NO(3) and F. The study revealed that 65% of the samples were found to be unsuitable for drinking purposes in the pre monsoon season and 45% in the post monsoon due to excess nitrate (>45 mg/l) content in the ground water. Among the different seasons and environs, nitrate was in highest concentration in the granitic terrain and canal command areas during pre monsoon season. The nitrate was found to decrease with depth in all the hydrogeological set-ups in both the seasons. Intense agriculture practices, improper sewerage and organic waste disposal methods were observed to contribute nitrate to the shallow and moderately deep aquifers. 相似文献
346.
Brooks MC Annable MD Rao PS Hatfield K Jawitz JW Wise WR Wood AL Enfield CG 《Journal of contaminant hydrology》2002,59(3-4):187-210
The partitioning tracer technique for dense nonaqueous phase liquid (DNAPL) characterization was evaluated in an isolated test cell, in which controlled releases of perchloroethylene (PCE) had occurred. Four partitioning tracer tests were conducted, two using an inverted, double five-spot pumping pattern, and two using vertical circulation wells. Two of the four tests were conducted prior to remedial activities, and two were conducted after. Each test was conducted as a "blind test" where researchers conducting the partitioning tracer tests had no knowledge of the volume, method of release, nor resulting spatial distribution of DNAPL. Multiple partitioning tracers were used in each test, and the DNAPL volume estimates varied significantly within each test based on the different partitioning tracers. The tracers with large partitioning coefficients generally predicted a smaller volume of PCE than that expected based on the actual release volume. However, these predictions were made for low DNAPL saturations (average saturation was approximately 0.003), under conditions near the limits of the method's application. Furthermore, there were several factors that may have hindered prediction accuracy, including tracer degradation and remedial fluid interference. 相似文献
347.
Occurrence of estrogenic effects in sewage and industrial wastewaters in Beijing, China 总被引:1,自引:0,他引:1
Estrogenic potencies of the effluents or water samples from wastewater treatment plants (WWTPs), industries and hospitals and some receiving rivers in Beijing city were estimated by using a human estrogen receptor recombinant yeast assay. Estrogenic activity of industrial wastewaters was found to range from 0.1 to 13.3 ng EEQ/L and decreased to the range of 0.03-1.6 ng EEQ/L after treatment. Estrogenic activity in WWTP influent ranged from 0.3 to 1.7 ng EEQ/L and decreased to the range of 0.05-0.5 ng EEQ/L after treatment. In the receiving river waters, the estrogenic effect range was 0.1-4.7 ng EEQ/L. These data suggest that treated industrial effluents and WWTP effluents of concern are not the only source of estrogenic pollution in surface waters in Beijing city. EEQ levels in Beijing river water are likely attributable to untreated municipal and industrial wastewaters discharged directly into the river. 相似文献
348.
Kamaraj Rajkumar Rao Yarrapragada K.S.S. B Balakrishna 《Environmental science and pollution research international》2022,29(29):43770-43785
Environmental Science and Pollution Research - Biodiesel is a renewable, clean-burning diesel replacement that can be used in existing diesel engines without modification. Biodiesel is among the... 相似文献
349.
六六六热解废渣中2,3,7,8—取代PCDDs和PCDFs的测定 总被引:4,自引:3,他引:4
采用HPLC和GC/MS法对六六六热解废渣中的PCDDs和PCDFs进行了测定,使用此种方法,于废渣中检出了所有2,3,7,8-取代的同系物。此外,还根据各CDDs,CDFs的毒性当量因子TEFs,计算了废渣的毒性当量TEQs,约为612-924μg/g。分析表明,OCDD是含量最丰富的导构体,而1,2,3,4,6,7,8-HpCDD,1,2,3,4,6,7,8-HpCDF和1,2,3,4,7,8 相似文献
350.
Satyavathi Chinni Ritindra N. Khan V. Uma Devi Prabhakara Rao Yallaprgada 《Chemistry and Ecology》2013,29(3):157-170
Lead tolerance in Penaeus indicus post-larvae (PL) was studied in relation to the water variables: salinity, temperature and pH. the LC50 for 96 hrs was 7.22 ppm at ambient conditions of salinity (20%o), temperature (29°C) and pH (7.2). the post-larvae were found to be sensitive to salinity variations with a significant (P < 0.05) low LC50 values at lower (2%o) and higher (29%o) ranges. Though a decrease in LC50 value was observed both at higher (45°C) and lower (10°C) temperatures, it was significantly (P < 0.05) low only at higher temperature indicating more toxicity. the LC50 values also showed a significant (P < 0.05) decrease in acidic (pH 2.8) and alkaline (pH 11.0) conditions. the data indicate that lead toxicity increases in the PL of P. indicus with variations in the water variables. 相似文献