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521.
我国4个大城市空气PM_(2.5)、PM_(10)污染及其化学组成 总被引:49,自引:3,他引:49
报告了 1 995~ 1 996年在中国的广州、武汉、兰州、重庆 4大城市 8个采样点 PM2 .5 、PM2 .5~ 1 0 和 PM1 0 的监测结果。结果表明 ,1 995年 PM2 .5 年均值浓度为 57~ 1 60 μg/m3,比美国 1 997年颁布的标准值 (1 5μg/m3)高 2 .8~ 9.7倍。PM1 0 年日均值为 95~ 2 73μg/m3。除武汉市 1个对照点外 ,其余 7个监测点的 PM1 0 均超过我国空气质量二极标准 (1 0 0μg/m3)2 8%~ 1 73 % ,比美国标准 (50μg/m3)超过更多 ,说明污染是相当严重的。用 XRF分析了 PM2 .5 、PM2 .5~ 1 0 中 4 2种化学元素 ,结果表明 ,燃煤、燃油和其它工业污染的元素 As、Pb、Se、Zn、Cu、Cl、Br、S在这些颗粒物中有明显富集 ,特别是在PM2 .5 中的富集倍数达数十倍至数万倍 ,对人体健康有很大危害 相似文献
522.
Chemical and mineralogical forms of Cu and Ni in contaminated soils from the Sudbury mining and smelting region, Canada 总被引:10,自引:0,他引:10
Adamo P Dudka S Wilson MJ McHardy WJ 《Environmental pollution (Barking, Essex : 1987)》1996,91(1):11-19
Available information on soil contamination by trace elements in the Sudbury Cu/Ni mining and smelting region consists largely of total elemental concentration data. Little is known about the mode of occurrence and behaviour of Cu and Ni (the main metallic contaminants) in the soils of the region. In this study, sequential extraction and Scanning Electron Microscopy and Energy Dispersive X-ray Analysis (SEM/EDX) observations were complementarily used to define Cu and Ni forms in the Sudbury soils, so as to assess metal mobility. Most Cu (on average 75%) was associated with 'non-residual' soil forms, whereas Ni was mainly (on average 60%) associated with inorganic 'residual' forms of a sulphide and oxide nature. Therefore, Cu occurs in the soils in more mobile forms than Ni. Consequently, Cu should be removed from these soils at a faster rate than Ni. This is an unusual finding, because generally Ni is known to be more mobile in soils than Cu. SEM/EDX analysis confirmed the greater Cu mobility by showing that the metal was strongly associated with organic matter and was homogeneously distributed on the clay fraction surfaces. Nickel occurred alone or was associated with Fe oxides in various size fractions. Both elements were found as sulphides but Ni was often included in the silicate matrices of spherical particles in associations with Fe. SEM/EDX observations have shown that Cu and Ni are associated with soil forms which would not have been predicted by the sequential extraction alone, such as carbonaceous material, silicate spheres and carbonate particles, supporting complementary use of the two techniques. 相似文献
523.
Roberts BR Wilson LR Cascino JJ Smith GP 《Environmental pollution (Barking, Essex : 1987)》1987,45(2):81-86
Carbon-14-labelled ethylenediurea (EDU), synthesised from diethylenetriamine and (14)C-urea, was stem-injected into 2-year-old seedlings of sugar maple, white ash, flowering dogwood and flowering crabapple. At time intervals ranging from 1 h to 42 days after treatment, macroautoradiographs of leaf, stem and root tissue were made to determine relative distribution patterns of labelled chemical. Translocation of (14)C-EDU was very rapid and predominantly acropetal, especially after the first few hours. Maximum quantities of (14)C were found in leaf tissue approximately 7-10 days following injection, after which the intensity of the labelled chemical declined over the remainder of the study (42 days). Distribution patterns of (14)C-EDU were correlated with observed levels of protection afforded most plants when the chemical is injected 7 days before fumigation with ozone. 相似文献
524.
Elizabeth A. Law Nathan J. Bennett Christopher D. Ives Rachel Friedman Katrina J. Davis Carla Archibald Kerrie A. Wilson 《Conservation biology》2018,32(2):294-303
Conservation decisions increasingly involve multiple environmental and social objectives, which result in complex decision contexts with high potential for trade‐offs. Improving social equity is one such objective that is often considered an enabler of successful outcomes and a virtuous ideal in itself. Despite its idealized importance in conservation policy, social equity is often highly simplified or ill‐defined and is applied uncritically. What constitutes equitable outcomes and processes is highly normative and subject to ethical deliberation. Different ethical frameworks may lead to different conceptions of equity through alternative perspectives of what is good or right. This can lead to different and potentially conflicting equity objectives in practice. We promote a more transparent, nuanced, and pluralistic conceptualization of equity in conservation decision making that particularly recognizes where multidimensional equity objectives may conflict. To help identify and mitigate ethical conflicts and avoid cases of good intentions producing bad outcomes, we encourage a more analytical incorporation of equity into conservation decision making particularly during mechanistic integration of equity objectives. We recommend that in conservation planning motivations and objectives for equity be made explicit within the problem context, methods used to incorporate equity objectives be applied with respect to stated objectives, and, should objectives dictate, evaluation of equity outcomes and adaptation of strategies be employed during policy implementation. 相似文献
525.
Machado W Rodrigues AP Bidone ED Sella SM Santelli RE 《Environmental science and pollution research international》2011,18(6):1033-1036
Purpose
Metal bioavailability-based sediment quality analysis, inferred from geochemical partitioning data, may contribute to improve sediment management policies. This is important because decision-making processes should not give similar priorities to sediments offering contrasting environmental risks associated to metal bioavailability. However, current uses of Sediment Quality Guidelines (SQGs) as interpretive tools to support decisions about dredging-related activities have not considered the changes in metal bioavailability upon sediment resuspension. 相似文献526.
527.
David F. Miller Wm. E. Wilson Jr. Robert G. Kling 《Journal of the Air & Waste Management Association (1995)》2013,63(7):414-417
An electrochemical instrument of the type commonly used to monitor total oxidants was adapted to measure acid gases such as SO2, HCI, and HCO2H. By using chemical methods of treating the air sample prior to absorption, it is possible to monitor for specific oxidants and acids. Measurements of NO, NOx, and SO2 during smog-chamber experiments were found to be in good agreement with measurements made by other methods. 相似文献
528.
Richard D. Wilson David W. Minnotte 《Journal of the Air & Waste Management Association (1995)》2013,63(10):761-766
Several existing federal and state provisions act to reduce the cost to in dustry of controlling air pollution. Included are the federal corporate income tax, depreciation allowances, investment credits, small Business Administration loans, Economic Development Administration aid, and state tax laws. These provisions give government assistance to industry amounting to as much as 59 percent of the cost of air pollution control. Numerous bills have been introduced in Congress that would give additional government aid to industry in the form of special across-the-board tax allowances for air pollution control equipment. A typical bill of this type would result in the government bearing an additional 11 percent of these costs. There are several possible objectives for this kind of additional aid; however, none of these seem valid when the amount of present assistance is recognized. From this analysis, it would seem that additional across-the-board tax subsidies for air pollution control equipment are neither required nor advisable. Future studies and/or experience may show certain firms or industries for which air pollution control will be too great a burden and for which additional government assistance is advisable. When such cases are found, legislation should be enacted only after the pros and cons of the various assistance methods are considered. 相似文献
529.
Wm. E. Wilson Jr Arthur Levy 《Journal of the Air & Waste Management Association (1995)》2013,63(6):385-390
There is an appreciable chemical interaction between SO2 and photochemical smog which depends on the concentration of SO2 and water vapor. The rate of decay of SO2 concentration is greatly increased in the presence of photochemical smog. With 0.75 ppm SO2, a light-scattering aerosol is produced in dry systems and systems at 22 and 55% relative humidity (RH). Aerosol is not observed until after the NO2 peak has been reached and the NO concentration has fallen to a very low value. The formation of aerosol corresponds in time to the region of most rapid decrease in the SO2 profile. In systems at 65% RH or with smaller amounts of SO2, no light scattering is observed, but the percentage of SO2 disappearing is greater. In relatively dry systems the presence of SO2 results in a general slowing down of the photochemical smog reactions. In systems containing water vapor concentrations comparable to those found in the atmosphere, the inhibiting influence of SO2 on the smog reaction is less pronounced. However, the maximum concentration of oxidant produced by the photochemical smog reactions is significantly lower when SO2 is present. 相似文献
530.
Robert B. Snyder W. Ira Wilson Irving Johnson Albert A. Jonke 《Journal of the Air & Waste Management Association (1995)》2013,63(10):975-981
The information presented in this paper is directed to engineers who are involved with environmental emissions from coal conversion plants. Synthetic sorbents were investigated as an alternative to natural sorbents (limestone) for the removal of SO2 from the combustion gas in a fluidized-bed coal combustor. The sulfation rate of a synthetic sorbent, CaO in α-AI2O3, was determined as a function of gas composition, temperature, and calcium concentration in the sorbent. The reaction was found to be diffusion-controlled above 850°C and kinetically controlled at lower temperatures. The physical characteristics of the support material have a major effect oh the sulfation kinetics. Porosity measurements indicated that supports containing large pores (>0.2 µm) produced sorbents having high sulfation rates and that pores with diameters less than 0.2 µm did not contribute significantly to the capture of SO2. The sorbents SrO in α-AI2O3 and BaO in α-AI2O3 had lower SO2 capture rates than did CaO in α-AI2O3. The alkali metal oxide sorbents K2O and Na2O in α-AI2O3 captured SO2 much faster than did the alkaline earth metal oxides. 相似文献