首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   204篇
  免费   6篇
  国内免费   1篇
安全科学   14篇
废物处理   3篇
环保管理   37篇
综合类   24篇
基础理论   49篇
污染及防治   54篇
评价与监测   18篇
社会与环境   10篇
灾害及防治   2篇
  2022年   3篇
  2021年   8篇
  2020年   2篇
  2019年   6篇
  2018年   10篇
  2017年   5篇
  2016年   10篇
  2015年   6篇
  2014年   5篇
  2013年   19篇
  2012年   5篇
  2011年   7篇
  2010年   7篇
  2009年   6篇
  2008年   6篇
  2007年   7篇
  2006年   9篇
  2005年   7篇
  2004年   5篇
  2003年   4篇
  2002年   2篇
  2001年   3篇
  2000年   3篇
  1998年   2篇
  1997年   5篇
  1996年   1篇
  1995年   5篇
  1994年   4篇
  1993年   2篇
  1992年   2篇
  1991年   2篇
  1990年   3篇
  1989年   1篇
  1988年   2篇
  1987年   3篇
  1985年   1篇
  1984年   6篇
  1983年   2篇
  1982年   1篇
  1981年   3篇
  1980年   1篇
  1979年   4篇
  1978年   1篇
  1977年   6篇
  1976年   2篇
  1975年   2篇
  1974年   1篇
  1972年   1篇
  1971年   1篇
  1969年   1篇
排序方式: 共有211条查询结果,搜索用时 15 毫秒
101.
Papermill biosolids (PB) can provide multiple benefits to the soil system. The purpose of this study was to quantify the effects of a high C/N ratio (C/N = 100) de-inked PB on soil physical and chemical properties, including soil bulk density, infiltration rates, wet aggregate stability, total soil carbon, and heavy metal concentrations. Four rates of PB (0, 50, 100, and 150 Mg ha(-1)) were applied annually, for up to 3 yr, on four agricultural soils in Ontario, Canada. Decreases in soil bulk density between 0.27 and 0.35 g cm(-3), relative to the nonamended treatment, were observed in soils receiving PB treatments over 3 yr. Total soil carbon increased within 1 yr on PB-amended soils planted to soybeans but not on soils planted to corn. Hydraulic conductivities (K fs) were greater in all soils receiving PB amendments relative to the nonamended treatment throughout the study. Other properties measured, such as pH and electrical conductivity, were relatively unchanged after 2 yr of PB applications. While some increases in heavy metal accumulation occurred, there were no clear trends observed at any of the sites related to PB rates. The results of this study provide support to the idea that annual applications of PB can add significantly to the stability of soil structure.  相似文献   
102.
This paper reviews the evolution of energy use in Denmark since the early 1970s, in order to shed light on the future path of energy use in Denmark, with particular emphasis on the role of energy efficiency. Improvements in end-use energy efficiency reduced primary energy requirements in Denmark by 22% between 1972 and 1988. This change accounts for two-thirds of the decline in the ratio of energy use to gross domestic product that occurred during this time: the rest of the decline was caused by changes in the mix of goods and services produced and consumed by the Danes. Total energy savings achieved between 1972 and 1988 in Denmark ranked among the highest measured in any major OECD country. Overall, most of the energy savings in Denmark were brought about through improvements in technology. Short-term changes in consumer behaviour were significant in reducing energy needs for space heating and transport. An important stimulus for improved efficiency was higher energy prices, led in no small part by significant taxes imposed on small consumers of heating oil, electricity and motor fuels.  相似文献   
103.
Environmental Science and Pollution Research - The present research was devoted to water decontamination through the valorization of cellulosic fibers for the preparation of performing biosorbent,...  相似文献   
104.
Management strategies to reduce the risks to human life and property from wildfire commonly involve burning native vegetation. However, planned burning can conflict with other societal objectives such as human health and biodiversity conservation. These conflicts are likely to intensify as fire regimes change under future climates and as growing human populations encroach farther into fire‐prone ecosystems. Decisions about managing fire risks are therefore complex and warrant more sophisticated approaches than are typically used. We applied a multicriteria decision making approach (MCDA) with the potential to improve fire management outcomes to the case of a highly populated, biodiverse, and flammable wildland–urban interface. We considered the effects of 22 planned burning options on 8 objectives: house protection, maximizing water quality, minimizing carbon emissions and impacts on human health, and minimizing declines of 5 distinct species types. The MCDA identified a small number of management options (burning forest adjacent to houses) that performed well for most objectives, but not for one species type (arboreal mammal) or for water quality. Although MCDA made the conflict between objectives explicit, resolution of the problem depended on the weighting assigned to each objective. Additive weighting of criteria traded off the arboreal mammal and water quality objectives for other objectives. Multiplicative weighting identified scenarios that avoided poor outcomes for any objective, which is important for avoiding potentially irreversible biodiversity losses. To distinguish reliably among management options, future work should focus on reducing uncertainty in outcomes across a range of objectives. Considering management actions that have more predictable outcomes than landscape fuel management will be important. We found that, where data were adequate, an MCDA can support decision making in the complex and often conflicted area of fire management.  相似文献   
105.
Price JN  Hiiesalu I  Gerhold P  Pärtel M 《Ecology》2012,93(6):1290-1296
The existence of deterministic assembly rules for plant communities remains an important and unresolved topic in ecology. Most studies examining community assembly have sampled aboveground species diversity and composition. However, plants also coexist belowground, and many coexistence theories invoke belowground competition as an explanation for aboveground patterns. We used next-generation sequencing that enables the identification of roots and rhizomes from mixed-species samples to measure coexisting species at small scales in temperate grasslands. We used comparable data from above (conventional methods) and below (molecular techniques) the soil surface (0.1 x 0.1 x 0.1 m volume). To detect evidence for nonrandom patterns in the direction of biotic or abiotic assembly processes, we used three assembly rules tests (richness variance, guild proportionality, and species co-occurrence indices) as well as pairwise association tests. We found support for biotic assembly rules aboveground, with lower variance in species richness than expected and more negative species associations. Belowground plant communities were structured more by abiotic processes, with greater variability in richness and guild proportionality than expected. Belowground assembly is largely driven by abiotic processes, with little evidence for competition-driven assembly, and this has implications for plant coexistence theories that are based on competition for soil resources.  相似文献   
106.
Rats excreted the 14C from a single oral dose of N-isopropyl-N-[14C]phenyloxamic acid [I, a soil metabolite from 2-chloro-N-isopropylacetanilide (propachlor)] in approximately equal quantities in the urine (49.2%) and feces (48.2%). A milking goat given daily oral doses of [14C]-I (1 mg of I three times daily) excreted more 14C in the feces (56.6%) than it excreted in the urine. From both species, I accounted for 97 to 100% of the urinary 14C, and all of the 14C that was extractable from the feces (73 to 75% of the 14C in feces was extractable with methanol). Goat milk samples collected 16 hr after the last dose contained no detectable 14C. Tissue residues of 14C were determined.  相似文献   
107.
108.
Fifteen metabolites of crufomate (4-tert-butyl-2-chlorophenyl methyl methylphosphoramidate, I) were identified in the excreta from rats given single oral doses of I. Compound I was not detected in either the urine or the feces. The metabolic reactions observed were N-and O-demethylation, oxidations of the t-butyl moiety, replacement of the H-N-CH3 with an OH moiety, hydrolysis of the phosphoramidate moiety to yield the phenol, conjugation with glucuronic acid, and combinations of these reactions. No ring dehalogenation or ring substitution was observed.  相似文献   
109.
Summary Exploitation of energy resources need not imply irreperable damage to our physical environment. Unfortunately lack of involvement at the policy planning stage hinders significant improvements despite the enthusiastic but fragmented endeavours of interested parties.Evaluation of alternative strategies must keep pace with prospecting and engineering to achieve real influence upon the ultimate location, scale and form of development.Fruitful examination of policy alternatives is hindered by the competition between energy industries in the UK perpetuated by the apparent lack of a national energy strategy.The fast increasing bulk of environmental guidelines and proposed European legislation will not of itself prevent the significant environmental impact of energy exploitation.There is as yet no legislation in the United Kingdom requiring a developer to submit an environmental impact assessment with a planning application. However, many recent project proposals have been accompanied by such, either voluntarily or at the request of the local planning authority. The quality of such submissions ranges from the superficial to substantial, but few demonstrate evidence of environmental influence on policy formulation, alternative site selection or development characteristics.Recent experience in the UK has achieved significant success in the early introduction of physical planning and environmental criteria during the exploration of Western Europe's largest recoverable deep coal reserves.Environmental influence was achieved through close collaboration between client and consultants. Early discussion with local authorities and other agencies established during coal field exploration provided the basis for ongoing consultation during the four-year study period. Publication of consultants' findings and submission of planning proposals culminated in a public inquiry providing opportunity for public involvement over 84 days of project examination.David Price is an Architect and Town Planner in private practice with extensive experience in urban and regional planning and environmental evaluation in the UK and abroad. He is also a member of Land Planning Group, a multi-disciplined design and planning consultancy.  相似文献   
110.
Putting cash values on the environment facilitates commoditization and political capture of evaluation. However, individual citizens may also wish to know the appropriate trade‐off of values, in order to use political power properly. Willingness‐to‐pay offers insight into consumers’ valuation of landscape, but routine application of economic methods to land use decisions meets major problems, especially the data needs of cost — benefit analysis in face of the urgency of decisions, and the insensitivity of conventional methods to subtle landscape changes. These problems require the citizen‐as‐consumer to make personal judgements of value, but to link those values to a cash scale for the purpose of making trade‐offs. Such judgements can be entered into an orderly framework, in which the judgements can be exposed for comment, which itself exposes the assumptions of commentators. The decision about routing electricity transmission lines in Scotland provides an example. Recent interest in environmental economics gives the opportunity to broaden the scope of the method.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号