全文获取类型
收费全文 | 129篇 |
免费 | 13篇 |
国内免费 | 11篇 |
专业分类
安全科学 | 10篇 |
废物处理 | 3篇 |
环保管理 | 19篇 |
综合类 | 51篇 |
基础理论 | 31篇 |
污染及防治 | 11篇 |
评价与监测 | 23篇 |
社会与环境 | 5篇 |
出版年
2023年 | 5篇 |
2022年 | 2篇 |
2021年 | 7篇 |
2020年 | 8篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 9篇 |
2016年 | 7篇 |
2015年 | 8篇 |
2014年 | 6篇 |
2013年 | 11篇 |
2012年 | 6篇 |
2011年 | 7篇 |
2010年 | 2篇 |
2009年 | 7篇 |
2008年 | 6篇 |
2007年 | 9篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1992年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
排序方式: 共有153条查询结果,搜索用时 15 毫秒
31.
环境恶臭评价方法的新探讨 总被引:6,自引:0,他引:6
对环境恶臭物质的臭气强度评价方法进行了探讨,求出了8种臭气物质的线性相关系数r、a、b值,阐明了嗅觉评价与臭气物质浓度检测评价间的内在联系(C′/C=10△I/b)。提出了H2S、NH3的浓度随强度降低的“10倍衰减规律”和“5倍衰减规律”,并将浓度估计值与实测值进行了比较。 相似文献
32.
含硫原油炼制过程的恶臭污染与防治 总被引:1,自引:0,他引:1
陈宏国 《石油化工环境保护》1997,(1):23-26
含硫原油炼制过程中,原料、中间体、产品中含流量富,恶臭污染源数量增多,污染加重.恶臭污染的防治办法有改进炼油生产工艺、加强环保管理、采取污染治理措施等。 相似文献
33.
34.
35.
Abstract: Systematic conservation planning typically requires specification of quantitative representation targets for biodiversity surrogates such as species, vegetation types, and environmental parameters. Targets are usually specified either as the minimum total area in a conservation-area network in which a surrogate must be present or as the proportion of a surrogate's existing spatial distribution required to be in the network. Because the biological basis for setting targets is often unclear, a better understanding of how targets affect selection of conservation areas is needed. We studied how the total area of conservation-area networks depends on percentage targets ranging from 5% to 95%. We analyzed 12 data sets of different surrogate distributions from 5 regions: Korea, Mexico, Québec, Queensland, and West Virginia. To assess the effect of spatial resolution on the target-area relationship, we also analyzed each data set at 7 spatial resolutions ranging from 0.01°× 0.01° to 0.10°× 0.10°. Most of the data sets showed a linear relationship between representation targets and total area of conservation-area networks that was invariant across changes in spatial resolution. The slope of this relationship indicated how total area increased with target level, and our results suggest that greater surrogate representation requires significantly more area. One data set exhibited a highly nonlinear relationship. The results for this data set suggest a new method for setting targets on the basis of the functional form of target-area relationships. In particular, the method shows how the target-area relationship can provide a rationale for setting targets solely on the basis of distributional information about surrogates. 相似文献
36.
The Convention on Biological Diversity's (CBD) strategic plan will expire in 2020, but biodiversity loss is ongoing. Scientists call for more ambitious targets in the next agreement. The nature-needs-half movement, for example, has advocated conserving half of Earth to solve the biodiversity crisis, which has been translated to protecting 50% of each ecoregion. We evaluated current protection levels of ecoregions in the territory of one of the CBD's signatories, the European Union (EU). We also explored the possible enlargement of the Natura 2000 network to implement 30% or 50% ecoregion coverage in the EU member states’ protected area (PA) network. Based on the most recent land-use data, we examined whether ecoregions have enough natural area left to reach such high coverage targets. We used a spatially explicit mixed integer programing model to estimate the least-cost expansion of the PA network based on 3 scenarios that put different emphasis on total conservation cost, ecological representation of ecosystems, or emphasize an equal share of the burden among member states. To realize 30% and 50% ecoregion coverage, the EU would need to add 6.6% and 24.2%, respectively, of its terrestrial area to its PA network. For all 3 scenarios, the EU would need to designate most recommended new PAs in seminatural forests and other semi- or natural ecosystems. Because 15 ecoregions did not have enough natural area left to implement the ecoregion-coverage targets, some member states would also need to establish new PAs on productive land, allocating the largest share to arable land. Thirty percent ecoregion coverage was met by protecting remaining natural areas in all ecoregions except 3, where productive land would also need to be included. Our results support discussions of higher ecoregions protection targets for post-2020 biodiversity frameworks. 相似文献
37.
Kate E. Watermeyer Gurutzeta Guillera-Arroita Payal Bal Michael J. Burgass Lucie M. Bland Ben Collen Chris Hallam Luke T. Kelly Michael A. McCarthy Tracey J. Regan Simone Stevenson Brendan A. Wintle Emily Nicholson 《Conservation biology》2021,35(2):492-501
Global biodiversity indices are used to measure environmental change and progress toward conservation goals, yet few indices have been evaluated comprehensively for their capacity to detect trends of interest, such as declines in threatened species or ecosystem function. Using a structured approach based on decision science, we qualitatively evaluated 9 indices commonly used to track biodiversity at global and regional scales against 5 criteria relating to objectives, design, behavior, incorporation of uncertainty, and constraints (e.g., costs and data availability). Evaluation was based on reference literature for indices available at the time of assessment. We identified 4 key gaps in indices assessed: pathways to achieving goals (means objectives) were not always clear or relevant to desired outcomes (fundamental objectives); index testing and understanding of expected behavior was often lacking; uncertainty was seldom acknowledged or accounted for; and costs of implementation were seldom considered. These gaps may render indices inadequate in certain decision-making contexts and are problematic for indices linked with biodiversity targets and sustainability goals. Ensuring that index objectives are clear and their design is underpinned by a model of relevant processes are crucial in addressing the gaps identified by our assessment. Uptake and productive use of indices will be improved if index performance is tested rigorously and assumptions and uncertainties are clearly communicated to end users. This will increase index accuracy and value in tracking biodiversity change and supporting national and global policy decisions, such as the post-2020 global biodiversity framework of the Convention on Biological Diversity. 相似文献
38.
对三点比较式臭袋法的浅见 总被引:1,自引:0,他引:1
蔡云飞 《环境监测管理与技术》2013,25(4):45-47
针对臭气浓度的标准分析方法——三点比较式臭袋法,在分析过程中引入"无法辨别"选项,并建议稀释倍数由标准限值确定。经实际案例验证,采用改进后的方法,分析结果更接近现场的真实状况,从而提高了嗅辨结果的准确性,并减轻了嗅辨员的嗅觉疲劳。 相似文献
39.
ABSTRACT: An heuristic iterative technique based upon stochastic dynamic programming is presented for the analysis of the operation of a three reservoir ‘Y’ shaped hydroelectric system. The technique is initiated using historical inflow data for the downstream reservoir. At each iteration the optimal policies for the downstream hydroelectric generating unit are used to provide relative weightings or targets for operation of upstream reservoirs. New input inflows to the downstream reservoir are then obtained by running the historical streamflow record through the optimal policies for the upstream reservoirs. These flows are then used to develop a new operating policy for the downstream reservoir and hence new targets for the upstream reservoirs. The process is continued until the operating policies for each reservoir provide the same overall system benefit for two successive iterations. Results obtained from the procedure are compared to the results obtained by historical operation of the system. The procedure is shown to develop operating policies which give benefits which are as close to the historical benefits as can be expected given the choice of the number of storage state variables. 相似文献
40.