全文获取类型
收费全文 | 100篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 8篇 |
废物处理 | 2篇 |
环保管理 | 21篇 |
综合类 | 10篇 |
基础理论 | 29篇 |
污染及防治 | 24篇 |
评价与监测 | 8篇 |
社会与环境 | 3篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 2篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 8篇 |
2013年 | 13篇 |
2012年 | 4篇 |
2011年 | 5篇 |
2010年 | 1篇 |
2009年 | 4篇 |
2008年 | 3篇 |
2007年 | 3篇 |
2006年 | 2篇 |
2005年 | 4篇 |
2004年 | 1篇 |
2003年 | 3篇 |
2002年 | 5篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1989年 | 2篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1979年 | 2篇 |
1977年 | 3篇 |
排序方式: 共有105条查询结果,搜索用时 31 毫秒
1.
2.
Examination of car fleet records in Accra demonstrates an increasing proportion of catalytic converter-equipped cars in the relatively old car fleet (average age 13 years) due to their import from developed countries. However, only leaded petrol is sold in Ghana. Lead anti-knocking additives, which are known to affect catalyst activity and promote thermal sintering and mechanical abrasion, may increase Pt emissions. This possible synergism prompted the concomitant determination of Pb and Pt levels in road dust and roadside soils in Ghana. Both metals followed traffic density with higher concentrations in urban areas compared to remote sites. In urban areas, the range for Pb (365 +/- 93 microg g(-1) for dust and 291 +/- 76 microg g(-1) for soil) reflects precatalyst levels in Europe and the US, while the range for Pt (39 +/- 24 ng g(-1) for dust and 15 +/- 5.3 ng g(-1) for soil) is typical for the same countries. The elevated Pt concentrations were unexpected due to recent introduction of catalysts to Ghana compared to the prolonged use of catalysts in Europe and the US. 相似文献
3.
The National Forest Management Act (1976) specifies that multiresource inventories be conducted to provide baseline data for
development and, later, monitoring of national forest management plans. This mandate entails the most ambitious and complex
resource planning effort ever attempted. In this paper we evaluate the structure and use of current inventory-monitoring programs
and recommend a framework for gathering data to improve national forest planning. Current national guidelines are general
and provide only basic directions to forest-level planners. Forest inventories have traditionally concentrated on timber.
Although these inventories are often well designed, the questions we are now asking about forest resources have outgrown these
methods. Forest management is impeded by general confusion over definitions of resources and the interactions among them.
We outline a simple classification scheme that centers on identification of basic ecosystem elements that can be readily measured.
Furthermore, spatial and temporal scales must be considered in the design of inventory-monitoring programs. The concept of
ecological indicators is reviewed, and caution is advised in their use. Inventory-monitoring programs should be goal-directed
and based on as rigorous a statistical design as possible. We also review fundamental issues of variable selection, validation,
and sampling bias. We conclude by developing a flexible inventory-monitoring program that is designed to provide information
on individual characteristics of the environment, rather than being based on fixed definitions of resources. 相似文献
4.
ABSTRACT: Thames Water is one of ten regional Water Authorities established in 1974 to manage all water services in England and Wales. This paper looks back at water reorganization and reviews the achievements and highlights of the last three years. Constitutionally, Water authorities are a combination of a nationalized industry and local authority. This has advantages and disadvantages. Freedom of action, particularly in financial matters, is constrained by Government and official agencies. A severe pollution of the upper Thames and the drought of 1976 tested Thames Water's ability to deal with emergencies. Thames Water does not have an operational monopoly. Private Water Companies supply one third of the water demand and local authorities manage nearly all the sewers. But Thames Water's control over planning and investment ensures that the river basin is managed in a coordinated fashion. Tariff structure changes have led the Authority to bill all its consumers direct. The Thames is a small but intensively used river and vigilance is needed to maintain water quality. Thames Water is proud of the restoration of the tidal Thames from a typical grossly polluted metropolitan estuary to its present excellent condition. The British Government intends to establish a national water industry strategic planning organization but at the same time they affirm that there can be no departure from the principle of integrated river basin management. 相似文献
5.
Planning,governance and rural futures in Australia and the USA: revisiting the case for rural regional planning 总被引:2,自引:0,他引:2
T.H. Morrison Marcus B. Lane Michael Hibbard 《Journal of Environmental Planning and Management》2015,58(9):1601-1616
Rural regions in post-industrial countries confront significant new challenges, particularly in relation to climate, biodiversity, unconventional resource development and energy. Yet at a time when the contours of these challenges are still being sketched, and preliminary, planned interventions undertaken, the practice of rural planning finds itself at a low ebb. We examine two ‘critical cases’, one each from Australia and the USA, to explore the issues and options for capacity of rural regional planning to surmount these new challenges. Our examination indicates the urgent need for a renewed discourse on rural regional planning. 相似文献
6.
J.D. Eakins A.E. Lally R.S. Cambray D. Kilworth R.T. Morrison F. Pratley 《Journal of environmental radioactivity》1984,1(2):87-105
In order to study the deposition on vegetation of plutonium arising from the testing of nuclear weapons and discharges from nuclear facilities, sheep faeces were collected from the South-west and North of England. The plutonium content of faeces has been shown to be a reproducible and sensitive indicator of deposition on herbage and, with this technique, plutonium discharged from the Sellafield Works of British Nuclear Fuels LImited can be detected 60 km from the site. On moorland pastures the concentration of 239+240Pu in faeces, expressed as activity per gram of ash, is roughly equal numerically to the deposit of plutonium on 1 m2 of vegetation.Some of the plutonium ingested by a grazing sheep is absorbed and the highest concentrations are found in liver. The liver of a sheep grazing on pasture where the 239+240Pu concentration in faeces was about 2 pCi (74 mBq) g−1 of ash, was found to contain <1% of the Generalised Derived Limit for mutton and offal, and the meat <0·001%. 相似文献
7.
S. J. Morrison J. D. King R. J. Bobbie R. E. Bechtold D. C. White 《Marine Biology》1977,41(3):229-240
Changes in hydrolytic, respiratory,catabolic and lipid biosynthetic activities depend at least in part on successional changes in the microfloral populations of allochthonous plant litter incubated in a semi-tropical estuary. Initial colonization is by populations which have a high content of muramic acid relative to the adenosine triphosphate (ATP) and which are progressively displaced by a microflora with a lower ratio of muramic acid to ATP. Scanning electron micrography of the plant-litter microflora shows a succession of forms, with an initial bacterial colonization and its progressive displacement by more complex forms. Estimates of the microbial mass and the rates of phospholipid synthesis suggest that the detrital microflora has a relatively slow growth rate compared to its growth potential. 相似文献
8.
Temperature, salinity, bottom-sediment type, and zinc concentration all influenced Cd uptake by 4 marine bivalves (Mya arenaria, Mytilus edulis, Mulinia lateralis and Nucula proxima) in short-term static assay systems using 109Cd as a tracer. The experimental system consisted of aquaria containing 20 l of seawater maintained under controlled light and temperature conditions. The water contained either 5 or 20 g/l Cd and tracer. Distribution and kinetics of the metal were monitored in the water column and organisms. The results demonstrate that Cd uptake rates differed widely among the organisms tested. An increase in temperature increased Cd uptake rate by all test organisms. A decrease in salinity increased Cd uptake by all organisms tested. The presence of bottom sediment depresses Cd accumulation in some benthic animals. Zinc in concentrations of 0.5 mg/l substantially decreased Cd uptake by Mytilus edulis and Mulinia lateralis. It is suggested that all important species and environmental variables be considered when studying heavy-metal uptake by marine organisms or when establishing water-quality criteria. 相似文献
9.
10.
Spatial Relationships of Levees and Wetland Systems within Floodplains of the Wabash Basin,USA 下载免费PDF全文
Ryan R. Morrison Erin Bray Fernando Nardi Antonio Annis Quan Dong 《Journal of the American Water Resources Association》2018,54(4):934-948
Given the unique biogeochemical, physical, and hydrologic services provided by floodplain wetlands, proper management of river systems should include an understanding of how floodplain modifications influence wetland ecosystems. The construction of levees can reduce river–floodplain connectivity, yet it is unclear how levees affect wetlands within floodplains, let alone the cumulative impacts within an entire watershed. This paper explores spatial relationships between levee and floodplain wetland systems in the Wabash Basin, United States. We used a hydrogeomorphic floodplain delineation technique to map floodplain extents and identify wetlands that may be hydrologically connected to river networks. We then spatially examined the relationship between levee presence, wetland area, and other river network attributes within discrete subbasins. Our results show that cumulative wetland area is relatively constant in subbasins that contain levees, regardless of maximum stream order within the subbasin. In subbasins that do not contain levees, cumulative wetland area increases with maximum stream order. However, we found that wetland distributions around levees can be complex, and further studies on the influence of levees on wetland habitat may need to consider finer resolution spatial scales. 相似文献