全文获取类型
收费全文 | 106篇 |
免费 | 1篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 4篇 |
废物处理 | 7篇 |
环保管理 | 47篇 |
综合类 | 7篇 |
基础理论 | 17篇 |
污染及防治 | 12篇 |
评价与监测 | 9篇 |
社会与环境 | 1篇 |
灾害及防治 | 5篇 |
出版年
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 5篇 |
2014年 | 1篇 |
2013年 | 14篇 |
2012年 | 3篇 |
2011年 | 6篇 |
2010年 | 5篇 |
2009年 | 5篇 |
2008年 | 2篇 |
2007年 | 5篇 |
2006年 | 3篇 |
2005年 | 6篇 |
2004年 | 9篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1987年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有109条查询结果,搜索用时 265 毫秒
41.
42.
假如地球上没有人类据《新科学家》报道,毋庸置疑,人类是地球有史以来最具统治力的生物。仅仅数千年的时间,城市、农田和牧场就侵占了地球陆地超过1/3的面积。据估计,人类现在霸占了地球40%的生产力。人类的连番冲击让地球变得满目疮痍:草原变为耕地,森林夷为平地,地下蓄水层干枯;而核能废料、化学污染、入侵物种、生物灭绝及气候变暖都是人类活动造成的直接恶果。如果可能的话,与人类分享地球的其它生物会毫不犹豫地把我们“踢出”地球。现在,假设它们如愿以偿,地球上65亿人明天一夜之间从地球上消失,被送到遥远的星系接受再教育,那么,地球将会发生怎样的变化? 相似文献
43.
Geological CO2 capture and storage (CCS) is among the main near-term contenders for addressing the problem of global climate change. Even
in a baseline scenario, with no comprehensive international climate policy, a moderate level of CCS technology is expected
to be deployed, given the economic benefits associated with enhanced oil and gas recovery. With stringent climate change control,
CCS technologies will probably be installed on an industrial scale. Geologically stored CO2, however, may leak back to the atmosphere, which could render CCS ineffective as climate change reduction option. This article
presents a long-term energy scenario study for Europe, in which we assess the significance for climate policy making of leakage
of CO2 artificially stored in underground geological formations. A detailed sensitivity analysis is performed for the CO2 leakage rate with the bottom-up energy systems model MARKAL, enriched for this purpose with a large set of CO2 capture technologies (in the power sector, industry, and for the production of hydrogen) and storage options (among which
enhanced oil and gas recovery, enhanced coal bed methane recovery, depleted fossil fuel fields, and aquifers). Through a series
of model runs, we confirm that a leakage rate of 0.1%/year seems acceptable for CCS to constitute a meaningful climate change
mitigation option, whereas one of 1%/year is not. CCS is essentially no option to achieve CO2 emission reductions when the leakage rate is as high as 1%/year, so more reductions need to be achieved through the use of
renewables or nuclear power, or in sectors like industry and transport. We calculate that under strict climate control policy,
the cumulative captured and geologically stored CO2 by 2100 in the electricity sector, when the leakage rate is 0.1%/year, amounts to about 45,000 MtCO2. Only a little over 10,000 MtCO2 cumulative power-generation-related emissions are captured and stored underground by the end of the century when the leakage
rate is 1%/year. Overall marginal CO2 abatement costs increase from a few €/tCO2 today to well over 150 €/tCO2 in 2100, under an atmospheric CO2 concentration constraint of 550 ppmv. Carbon costs in 2100 turn out to be about 40 €/tCO2 higher when the annual leakage rate is 1%/year in comparison to when there is no CO2 leakage. Irrespective of whether CCS deployment is affected by gradual CO2 seepage, the annual welfare loss in Europe induced by the implementation of policies preventing “dangerous anthropogenic
interference with the climate system” (under our assumption, implying a climate stabilisation target of 550 ppmv CO2 concentration) remains below 0.5% of GDP during the entire century.
相似文献
Koen SmekensEmail: |
44.
Paul Polak Bob Nanes Deepak Adhikari 《Journal of the American Water Resources Association》1997,33(1):119-124
ABSTRACT: In areas where water is scarce, drip irrigation provides the most efficient way to conserve irrigation water, but its cost of £1000 an acre is prohibitive for most small farmers in developing countries. The cost was reduced by 90 percent by (1) making dripper lines moveable, so that each line reaches ten rows instead of one; (2) replacing 25-cent emitters with simple 0.70 mm holes punched by a heated needle; and (3) using £3.00 off-the-shelf 20 liter containers with cloth filters in place of expensive filter systems. This reduced the cost of a half-acre system to £50. The low cost system was field tested in the hill areas of Nepal, and in mulberry cultivation in Andhra Pradesh, India. Uniformity of flow from emitters was 73–84 percent. Small farmers reported that the low cost trickle irrigation system cut labor requirements in half, and doubled the area irrigated by the same amount of water. The low cost drip system is likely to be widely adopted by small farmers in semi-arid and hilly regions. 相似文献
45.
Samuel Veloz Leonardo Salas Bob Altman John Alexander Dennis Jongsomjit Nathan Elliott Grant Ballard 《Conservation biology》2015,29(4):1217-1227
Systematic conservation planning aims to design networks of protected areas that meet conservation goals across large landscapes. The optimal design of these conservation networks is most frequently based on the modeled habitat suitability or probability of occurrence of species, despite evidence that model predictions may not be highly correlated with species density. We hypothesized that conservation networks designed using species density distributions more efficiently conserve populations of all species considered than networks designed using probability of occurrence models. To test this hypothesis, we used the Zonation conservation prioritization algorithm to evaluate conservation network designs based on probability of occurrence versus density models for 26 land bird species in the U.S. Pacific Northwest. We assessed the efficacy of each conservation network based on predicted species densities and predicted species diversity. High‐density model Zonation rankings protected more individuals per species when networks protected the highest priority 10‐40% of the landscape. Compared with density‐based models, the occurrence‐based models protected more individuals in the lowest 50% priority areas of the landscape. The 2 approaches conserved species diversity in similar ways: predicted diversity was higher in higher priority locations in both conservation networks. We conclude that both density and probability of occurrence models can be useful for setting conservation priorities but that density‐based models are best suited for identifying the highest priority areas. Developing methods to aggregate species count data from unrelated monitoring efforts and making these data widely available through ecoinformatics portals such as the Avian Knowledge Network will enable species count data to be more widely incorporated into systematic conservation planning efforts. 相似文献
46.
Bob Baulch 《Disasters》1987,11(3):195-204
The traglic recent events in Ethiopia and other parts of Africa have again foccussed attention on the different anaytical approaches to the problems iof famine. Perhaps the most important analytical contribution to this field has been Sen's "entitlements approach." One of the case studies Sen used to articulate this approach was of the 1972–1973 famine in Wollo Province, Ethiopia. This article provides a provisional assessment of the famine process in the Wollo during 1982–1985 to set against the analysis by Sen of the earlier famine. Some striking contrasts are revealed. 相似文献
47.
48.
Robert?W.?ElnerEmail author Peter?G.?Beninger Daniel?L.?Jackson Tracy?M.?Potter 《Marine Biology》2005,146(6):1223-1234
49.
Distributed process modeling for regional assessment of coastal vulnerability to sea-level rise 总被引:2,自引:0,他引:2
Brett Bryan Nick Harvey Tony Belperio Bob Bourman 《Environmental Modeling and Assessment》2001,6(1):57-65
Sea-level rise involves increases in the coastal processes of inundation and erosion which are affected by a complex interplay of physical environmental parameters at the coast. Many assessments of coastal vulnerability to sea-level rise have been detailed and localised in extent. There is a need for regional assessment techniques which identify areas vulnerable to sea-level rise. Four physical environmental parameters – elevation, exposure, aspect and slope, are modeled on a regional scale for the Northern Spencer Gulf (NSG) study area using commonly available low-resolution elevation data of 10 m contour interval and GIS-based spatial modeling techniques. For comparison, the same parameters are modeled on a fine-scale for the False Bay area within the NSG using high-resolution elevation data. Physical environmental parameters on the two scales are statistically compared to coastal vulnerability classes as identified by Harvey et al. [1] using the Spearman rank-correlation test and stepwise linear regression. Coastal vulnerability is strongly correlated with elevation and exposure at both scales and this relationship is only slightly stronger for the high resolution False Bay data. The results of this study suggest that regional scale distributed coastal process modeling may be suitable as a first cut in assessing coastal vulnerability to sea-level rise in tide-dominated, sedimentary coastal regions. Distributed coastal process modeling provides a suitable basis for the assessment of coastal vulnerability to sea-level rise of sufficient accuracy for on-ground management and priority-setting on a regional scale. 相似文献
50.
The Great Basin Desert lies between the Sierra Nevada Mountains to the west and the Rocky Mountains to the east. Nearly 60%
of the area’s deserts and mountains (roughly 30 million ha) are managed by the U. S. Department of Interior’s Bureau of Land
Management. This area is characterized by low annual precipitation, diverse desert plant communities, and local economies
that depend on the products (livestock grazing, recreation, mining, etc.) produced by these lands. The ecological and economic
stability of the Great Basin is increasingly at risk due to the expansion of fire-prone invasive species and increase in wildfires.
To stem this loss of productivity and diversity in the Great Basin, the BLM initiated the “Great Basin Restoration Initiative”
in 1999 after nearly 0.7 million ha of the Great Basin burned in wildfires. The objective of the Great Basin Restoration Initiative
is to restore plant community diversity and structure by improving resiliency to disturbance and resistance to invasive species
over the long-term. To accomplish this objective, a strategic plan has been developed that emphasizes local participation
and reliance on appropriate science to ensure that restoration is accomplished in an economical and ecologically appropriate
manner. If restoration in the Great Basin is not successful, desertification and the associated loss of economic stability
and ecological integrity will continue to threaten the sustainability of natural resources and people in the Great Basin. 相似文献