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本文利用了1998—2012年中国241个城市的空间面板数据对中国雾霾污染和FDI的区域分布特征及空间溢出效应进行经验考察,结合系统广义矩估计(SGMM)方法构建了动态空间面板模型,采用了Moran’s I和Geary’s C指数对中国FDI与雾霾(PM_(2.5))污染空间自相关性进行了全域和局域分析。结果发现:(1)雾霾(PM_(2.5))污染与FDI存在显著的空间正相关性,证明了雾霾(PM_(2.5))污染空间的溢出效应以及FDI的辐射效应的存在。同时FDI高值集聚区域一般是雾霾(PM_(2.5))高值集聚区,FDI低值集聚区域一般是雾霾(PM_(2.5))低值集聚区,表明一个地区的引资效果和雾霾(PM_(2.5))污染在地理上的集聚密切相关。雾霾(PM_(2.5))污染表现出显著的"叠加效应"和"溢出效应",说明中国雾霾(PM_(2.5))污染在空间维度、时间维度以及时空维度上分别表现出交叉、累积、持续的演变特征。(2)全样本下,FDI对雾霾(PM_(2.5))浓度的影响表现出增促效应。FDI存量每升高1%,雾霾(PM_(2.5))浓度升高0.011%。(3)分地区样本下,东部城市FDI存量每升高1%,雾霾(PM_(2.5))浓度升高0.001 9%;中部城市FDI存量每升高1%,雾霾(PM_(2.5))浓度升高0.018 3%;而西部城市FDI存量对雾霾(PM_(2.5))浓度影响不显著。上述实证结果说明中国雾霾污染存在着显著的空间依赖性和区域异质性,FDI对中国大部分城市的雾霾污染存在显著的增促效应。 相似文献
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确定中国对外直接投资(OFDI)对CO2排放的影响路径,对"一带一路"沿线国家如何有效利用中国OFDI以实现可持续发展具有重要作用。该研究基于2003—2018年45个沿线国家的面板数据,应用具有阈值和动态特征的面板平滑转换回归(PSTR)模型,评估中国OFDI对CO2排放的直接效应和间接效应、线性效应和非线性效应。研究发现:(1)中国OFDI对沿线国家CO2排放的直接影响显著为负。(2)中国OFDI的规模效应增加了沿线国家CO2排放,其结构效应和技术效应进一步抑制了沿线国家CO2排放,且技术效应在间接效应中占有主导地位。(3)异质性分析表明,中国OFDI的碳减排效应更多体现在低收入国家。针对以上研究发现,文章认为沿线国家应持续引进中国OFDI,并通过提高能效和推广应用清洁能源打破经济发展的"不可持续性";中国政府应继续鼓励并引导具有竞争力的企业"走出去",充分发挥中国投资对东道国环境的改善作用,放大中国投资对低收入国家的技术溢出效应;中国应根据沿线国家经济发展水平对东道国实施差异化投资策略,实现中国投资环境效益最优化。 相似文献
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Abstract: Worldwide efforts have concentrated on developing monitoring methods that would enhance the assessment of progress toward achieving the 2010 conservation objectives of the Convention on Biological Diversity. Threat reduction assessment is one such method. It provides an indirect measure of the effects of a conservation project by evaluating changes in human‐induced direct threats to protected areas. We applied modified threat reduction assessments and the 2008 International Union for Conservation of Nature standardized lexicon for classification of threats to Horsh Ehden and Al‐Shouf Cedar nature reserves in Lebanon. Our goal was in part to test the suitability of this tool for improving monitoring and management effectiveness of protected forests in Lebanon. In Horsh Ehden, composite threats decreased by 24% from 1997 to 2002, and then increased from 2002 to 2009 by 78% in the core area of the reserve and by 118% in the reserve's buffer zone (surrounds core area, conservation and recreational activities allowed). In Al‐Shouf Cedar reserve threats decreased by 51% from 2006 to 2009. Management teams from both reserves have integrated the use of this method to prioritize actions for new management plans. We believe that in Lebanon and other countries with limited resources and weak monitoring programs or that are experiencing political instability threat reduction assessments could be used to improve the effectiveness of protected areas management. 相似文献
306.
Joseph M. Colonell George R. Higgins 《Journal of the American Water Resources Association》1973,9(4):793-800
Hydrologic response, defined as the annual direct runoff divided by the annual precipitation, was computed for twenty-one watersheds in or near western Massachusetts, using a total of 232 years of hydrologic records. Variability of the results over the period of analysis was greater than is desirable to inspire confidence in the usefulness of the hydrologic response function; however, the results do suggest that the hydrologic response concept, with appropriate refinements, could be applied successfully to the problem of delineating hydrologic provinces and determination of drainage and storage in unregulated watersheds. 相似文献
307.
Dennis C. Cory John Daubert 《Journal of the American Water Resources Association》1981,17(6):1066-1070
ABSTRACT: An integral part of evaluating the net benefits generated by an existing or proposed irrigation project is the assessment of the associated impacts in commodity markets. Traditionally, these impacts have been measured by either assuming no change in commodity prices and calculating net returns to project farmers, or by allowing commodity prices to fall in accordance with a given elasticity of demand and subtracting commodity production costs from the associated area under the commodity demand curve. In either case, it is implicitly assumed that supply is perfectly inelastic. This article establishes that traditional approaches to measuring direct benefits are biased. Formulae are presented for calculating the maximum absolute and relative error which may result from using these techniques as a function of project size. Direct benefit estimates are then evaluated for three irrigation projects in Nebraska, illustrating how these results can be used to improve project evaluation procedures. 相似文献
308.
Yuri N. Skiba Valentina Davydova-Belitskaya 《Environmental Modeling and Assessment》2002,7(3):153-162
A method for estimating the impact of industrial emissions is suggested and applied to the Guadalajara City Metropolitan Area (GCMA). The method is based on solutions to the pollution transport model and its adjoint. Two equivalent direct and adjoint mean pollution concentration estimates are considered for ecologically important zones of the GCMA. The dependence of these estimates on the number, positions and emission rates of industrial plants, as well as on the wind and initial pollution distribution in the GCMA is qualitatively and quantitatively examined. It is shown that the adjoint model solutions serve as the influence functions providing valuable information on the role of each of the industrial plants in polluting different zones within the GCMA. These solutions have been calculated with a balanced and absolutely stable second-order finite-difference scheme based on the splitting method. A method for an optimal allocation of a new industrial plant is considered. 相似文献
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310.
J. D. Hewlett G. B. Cunningham C. A. Troendle 《Journal of the American Water Resources Association》1977,13(2):231-254
ABSTRACT: A relatively simple nonlinear equation was fitted to 468 stormflows larger than 0.05 area inches on 11 forested basins from New Hampshire to South Carolina, providing a predictive method for use on forest and wildlands in humid regions. Stormflow in area inches (Q?) was: where R is the mean value of Q/P for all P larger than one inch, P is storm rainfall in inches, and I is the initial flow rate in ft3/sec/mi2. S.E. was 0.3 inch of stormflow. Peakflow was similarly estimated, S.E. 26 ft3/sec/mi2. The R-index method is proposed as a practical tool in forest and wildland management. Similar to the SCS runoff curve number method, the R-index method requires no prior assumptions about infiltration capacities of forest lands, but calls for the mapping of all first-order streams for the average storage capacity index R, i.e., the mean hydrologic response of the source areas. Tested against the runoff curve method on four independent basins, predictions by the R-index method were considerably more accurate when field information normally available to planners and managers was used in both methods. 相似文献