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591.
本项目对立式循环流动系统内气体压力、流量变化的调节控制方法,通风机的能量消耗等实际工程问题,进行了一系列的试验研究。其研究成果可以用于其他工程设计项目,对提高我国通风除尘系统的设计质量有一定的现实意义。 相似文献
592.
垃圾渗滤液氨态氮与挥发性脂肪酸馏出规律研究 总被引:1,自引:0,他引:1
为了提高垃圾渗滤液氨态氮(NH4^+-N)与挥发性脂肪酸(VFA)联合滴定分析结果的准确性,试验研究了NH4^+-N与VFA的馏出规律,并在此基础上对联合滴定方法的优化进行了探讨。结果表明:测得的NH4^+-N质量浓度(Y1)、VFA浓度(Y2)与馏出液体积(X)分别符合函数关系式;联合滴定分析过程中,渗滤液样品NH4^+-N质量浓度应稀释至150mg/L-200mg/L,NH4^+-N馏出液应大于蒸馏液体积的60%;VFA分析应采用“一次蒸馏80%+二次蒸馏”的方式,且VFA二次馏出液应大于蒸馏液体积的75%(相对误差限εr〈5%)。 相似文献
593.
594.
City action is critical to achieving global visions for sustainability such as the UN’s Sustainable Development Goals (SDGs). However, SDG ‘localisation’ is complex procedure, with divergent outcomes depending on context and diverse city processes. This paper considers the operational challenges faced by city actors in taking on the SDGs, and subsequent implications for initiating local (and global) sustainability transitions. We analyse emergent approaches to SDG localisation within the Asia–Pacific, using a policy analysis framework (transition management) to assess transformation potential. We find that SDG localisation can influence urban sustainability, but effective implementation requires sufficient data, resourcing, and guidance—which are not readily, nor equally available to all city governments. City-to-city peer learning can accelerate SDG uptake, but realising the transformative ambition set out by the SDGs will require an approach to localisation that clearly demonstrates why and how any city government can and should engage with global sustainability frameworks. 相似文献
595.
郑州市环境空气中多环芳烃污染状况及变化规律的研究 总被引:3,自引:1,他引:2
对郑州市2004年环境空气中多环芳烃的污染状况及变化规律进行了初步研究,结果表明,郑州市环境空气中15种优控PAHs的浓度范围为未检出-698ng/m3,强致癌性物质苯并(a)芘的检出率为100%,其浓度范围为1.56~136ng/m3.PAHs类物质在不同季节的变化趋势为冬季>秋季>春季>夏季;在不同功能区变化趋势为工业区>混合区>交通密集区>文化区>对照区. 相似文献
596.
Mary F. Evans Scott M. Gilpatric Lirong Liu 《Journal of Environmental Economics and Management》2009,57(3):284-292
We model the optimal design of programs requiring heterogeneous firms to disclose harmful emissions when disclosure yields both direct and indirect benefits. The indirect benefit arises from the internalization of social costs and resulting reduction in emissions. The direct benefit results from the disclosure of previously private information which is valuable to potentially harmed parties. Previous theoretical and empirical analyses of such programs restrict attention to the former benefit while the stated motivation for such programs highlights the latter benefit. When disclosure yields both direct and indirect benefits, policymakers face a tradeoff between inducing truthful self-reporting and deterring emissions. Internalizing the social costs of emissions, such as through an emissions tax, will deter emissions, but may also reduce incentives for firms to truthfully report their emissions. 相似文献
597.
Thomas D. Harwood Xiangming Xu Marco Pautasso Mike J. Jeger Michael W. Shaw 《Ecological modelling》2009
We developed a stochastic simulation model incorporating most processes likely to be important in the spread of Phytophthora ramorum and similar diseases across the British landscape (covering Rhododendron ponticum in woodland and nurseries, and Vaccinium myrtillus in heathland). The simulation allows for movements of diseased plants within a realistically modelled trade network and long-distance natural dispersal. A series of simulation experiments were run with the model, representing an experiment varying the epidemic pressure and linkage between natural vegetation and horticultural trade, with or without disease spread in commercial trade, and with or without inspections-with-eradication, to give a 2 × 2 × 2 × 2 factorial started at 10 arbitrary locations spread across England. Fifty replicate simulations were made at each set of parameter values. Individual epidemics varied dramatically in size due to stochastic effects throughout the model. Across a range of epidemic pressures, the size of the epidemic was 5–13 times larger when commercial movement of plants was included. A key unknown factor in the system is the area of susceptible habitat outside the nursery system. Inspections, with a probability of detection and efficiency of infected-plant removal of 80% and made at 90-day intervals, reduced the size of epidemics by about 60% across the three sectors with a density of 1% susceptible plants in broadleaf woodland and heathland. Reducing this density to 0.1% largely isolated the trade network, so that inspections reduced the final epidemic size by over 90%, and most epidemics ended without escape into nature. Even in this case, however, major wild epidemics developed in a few percent of cases. Provided the number of new introductions remains low, the current inspection policy will control most epidemics. However, as the rate of introduction increases, it can overwhelm any reasonable inspection regime, largely due to spread prior to detection. 相似文献
598.
Ronald L. Ritschard James F. Cruise L. Upton Hatch 《Journal of the American Water Resources Association》1999,35(6):1585-1596
ABSTRACT: Competition for water resources is becoming an increasingly important issue in the southeastern U.S. The potential impacts of future precipitation and runoff estimated by a transient global climate model (HADCM2) on competing water resources in the Southeast has been conducted. Issues of agricultural management, irrigation water withdrawals, and water quality were studied over three time periods: 1974–1993, 2020–2039, and 2080–2099 in five water basins identified previously as exhibiting water-related problems. These basins, which encompass the boundary between Alabama and Mississippi, cover four important agricultural counties in Mississippi. Irrigation water requirements generated by crop growth models for corn, soybeans, and winter wheat were coupled with monthly runoff for the impacted basins estimated by the SWAT water balance model. The results of the study reveal that in the next 20–40 years water availability in the southern portions of the study area will decline as much as 10 percent during times when water requirements for agricultural production are crucial. Maintaining or expanding existing crop yields under future climate regimes may require additional irrigation water and increase competition among other uses such as domestic, industrial, recreational, and ecosystem quality. 相似文献
599.
MICHAEL R. BOSWELL ROBERT E. DEYLE RICHARD A. SMITH E. JAY BAKER 《Environmental management》1999,23(3):359-372
/ A method is presented for estimating probable public costs resulting from damage caused by hurricanes, measured as local government expenditures approved for reimbursement under the Stafford Act Section 406 Public Assistance Program. The method employs a multivariate model developed through multiple regression analysis of an array of independent variables that measure meteorological, socioeconomic, and physical conditions related to the landfall of hurricanes within a local government jurisdiction. From the regression analysis we chose a log-log (base 10) model that explains 74% of the variance in the expenditure data using population and wind speed as predictors. We illustrate application of the method for a local jurisdiction-Lee County, Florida, USA. The results show that potential public costs range from $4.7 million for a category 1 hurricane with winds of 137 kilometers per hour (85 miles per hour) to $130 million for a category 5 hurricane with winds of 265 kilometers per hour (165 miles per hour). Based on these figures, we estimate expected annual public costs of $2.3 million. These cost estimates: (1) provide useful guidance for anticipating the magnitude of the federal, state, and local expenditures that would be required for the array of possible hurricanes that could affect that jurisdiction; (2) allow policy makers to assess the implications of alternative federal and state policies for providing public assistance to jurisdictions that experience hurricane damage; and (3) provide information needed to develop a contingency fund or other financial mechanism for assuring that the community has sufficient funds available to meet its obligations. KEY WORDS: Hurricane; Public costs; Local government; Disaster recovery; Disaster response; Florida; Stafford Act 相似文献
600.