全文获取类型
收费全文 | 1559篇 |
免费 | 58篇 |
国内免费 | 178篇 |
专业分类
安全科学 | 117篇 |
废物处理 | 87篇 |
环保管理 | 877篇 |
综合类 | 395篇 |
基础理论 | 100篇 |
环境理论 | 1篇 |
污染及防治 | 100篇 |
评价与监测 | 66篇 |
社会与环境 | 24篇 |
灾害及防治 | 28篇 |
出版年
2023年 | 9篇 |
2022年 | 22篇 |
2021年 | 22篇 |
2020年 | 23篇 |
2019年 | 6篇 |
2018年 | 8篇 |
2017年 | 11篇 |
2016年 | 14篇 |
2015年 | 14篇 |
2014年 | 20篇 |
2013年 | 26篇 |
2012年 | 25篇 |
2011年 | 36篇 |
2010年 | 32篇 |
2009年 | 31篇 |
2008年 | 59篇 |
2007年 | 17篇 |
2006年 | 24篇 |
2005年 | 17篇 |
2004年 | 40篇 |
2003年 | 74篇 |
2002年 | 162篇 |
2001年 | 140篇 |
2000年 | 171篇 |
1999年 | 136篇 |
1998年 | 105篇 |
1997年 | 82篇 |
1996年 | 213篇 |
1995年 | 58篇 |
1994年 | 17篇 |
1993年 | 13篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 10篇 |
1988年 | 3篇 |
1986年 | 1篇 |
1985年 | 24篇 |
1984年 | 39篇 |
1983年 | 35篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 7篇 |
1978年 | 6篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1971年 | 15篇 |
1967年 | 1篇 |
排序方式: 共有1795条查询结果,搜索用时 312 毫秒
901.
An evaluation of the economic and environmental costs and benefits that would result if the Zorinsky Federal Building, located
in Omaha, Nebraska, USA, converted its current lighting system to a more energy-efficient system (i.e., joined the EPA's Green
Lights Program) was conducted. Lighting accounts for 20–25 percent of all electricity sold in the United States. Costs considered
in the study included the cost of retrofitting the building's existing lighting system and the cost of disposal of the current
lamps and ballast fixtures. Benefits included a reduction of electric utility costs and a reduction of emissions of SO2, NO
x
, CO2, and CO from electric utility power plants. Environmental and health issues for air pollutant emissions were also addressed.
The results showed that significant reductions in utility bills as well as reductions in air emissions would result from a
major building converting to a more energy efficient lighting system. The results showed that conversion of this large building
would reduce SO2 emissions by 14.6 tons/yr and NO
x
emissions by 6.3 tons/yr. In addition, the conversion would reduce annual energy costs by approximately $114,000. 相似文献
902.
Resource managers are increasingly being challenged by stakeholder groups to consider dam removal as a policy option and as
a tool for watershed management. As more dam owners face high maintenance costs, and rivers as spawning grounds for anadromous
fish become increasingly valuable, dam removal may provide the greatest net benefit to society. This article reviews the impact
of Endangered Species Act listings for anadromous fish and recent shifts in the Federal Energy Regulatory Commission's hydropower
benefit-costs analysis and discusses their implications for dam removal in California. We propose evaluative criteria for
consideration of dam removal and apply them to two case studies: the Daguerre and Englebright Dams on the Yuba River and the
Scott and Van Horne Dams on the South Eel River, California. 相似文献
903.
Centner TJ 《Environmental management》2001,28(5):599-609
Due to concentrations of animals at large facilities, animal feeding operations (AFOs) have emerged as a major potential source
of water pollution. The federal government regulates concentrated animal feeding operations under its point-source pollution
permitting regulations. A major determinant of whether an operation must apply for a permit is the number of animals at an
individual lot or facility. This paper examines federal mandatory controls and voluntary guidelines that seek to reduce contaminant
pollution from AFOs. Land treatment practices are delineated due to their importance in reducing the injurious by-products
of agricultural production. An evaluation of proposed revisions to federal regulations on confined animal feeding operations
suggests they diverge from their goal of controlling water pollution. Federal regulations focus on the size of operation and
amount of manure governed by the permitting process to the exclusion of other criteria related to the impairment of water
quality. Given the uncertainties about the amount of pollution from AFOs, lack of enforcement of existing regulations, localization
of problems, and possible alternatives for addressing the pollution, more demanding federal regulations may not form an appropriate
response. 相似文献
904.
Solid Waste Treatment as a High-Priority and Low- Cost Alternative for Greenhouse Gas Mitigation 总被引:5,自引:0,他引:5
The increased concern about environmental problems caused by inadequate waste management, as well as the concern about global
warming, promotes actions toward a sustainable management of the organic fraction of the waste. Landfills, the most common
means to dispose of municipal solid waste (MSW), lead to the conversion of the organic waste to biogas, containing about 50%
methane, a very active greenhouse gas (GHG). One unit of methane has a global warming potential of 21 computed for a 100-year
horizon or 56 computed for 20 years. The waste sector in Israel contributes 13% of total greenhouse gases (GHG) emissions
for a time horizon of 100 years (for a time horizon of 20 years, the waste sector contribution equals to more than 25% of
total GHG emissions). The ultimate goal is to minimize the amount of methane (CH4) by converting it to CO2. This can be achieved by physicochemical means (e.g., landfill gas flare, incineration) or by biological processes (e.g.,
composting, anaerobic digestion). Since the waste in Israel has a high organic material content, it was found that the most
cost-effective means to treat the degradable organic components is by aerobic composting (investment of less than US$ 10 to
reduce emission of one ton CO2 equivalent per year). Another benefit of this technology is the ability to implement it within a short period. The suggested
approach, which should be implemented especially in developing countries, could reduce a significant amount of GHG at relatively
low cost and short time. The development of a national policy for proper waste treatment can be a significant means to abate
GHG emissions in the short term, enabling a gain in time to develop other means for the long run. In addition, the use of
CO2 quotas will credit the waste sector and will promote profitable proper waste management. 相似文献
905.
Poncelet EC 《Environmental management》2001,27(1):13-25
Multistakeholder collaboration in the environmental realm has been increasing steadily over the past decade. This trend is
responding to several stimuli, including dissatisfaction with current regulatory regimes, a liberal economic climate emphasizing
global competitiveness and short-term returns, and the growing roles of the business and nongovernmental organization sectors
in the environmental policy arena. This paper grows out of ethnographic research conducted between 1994 and 1998 with four
environmental partnerships in Europe and the United States. The research found all of these partnerships to be marked by practices
of conflict minimization and diffusion. Drawing upon illustrative data from one of these case studies, a European Union level
initiative aimed at enabling sustainable development in Europe, the paper asks why this was the case, especially given the
diverse political and economic interests at stake and the history of contentious relations between the sectors in other venues.
Employing a theoretical perspective highlighting the sociohistoric factors involved in these processes, the paper suggests
that this proclivity toward nonconfrontational behavior stems in part from two sources: a prominent cultural model that conceptualizes
the partnership process as fundamentally nonconflictual in nature, and the promotion of the discourse of ecological modernization
over other competing discourses. The paper explores some of the implications of this finding and concludes that environmental
partnerships characterized by such nonconfrontational practices risk inadvertently encouraging the delegitimization of conflictual
approaches to environmental action and engendering a retreat from radical thinking and innovative environmental solutions. 相似文献
906.
Wyzga B 《Environmental management》2001,28(3):341-358
River engineers use sediment transport formulas to design regulated channels in which the river's ability to transport bedload
would remain in equilibrium with the delivery of materials from upstream. In gravel-bed rivers, a number of factors distort
the simple relationship between particle size and hydraulic parameters at the threshold of sediment motion, inherent in the
formulas. This may lead to significant errors in predicting the bedload transport rates in such streams and hence to instability
of their regulated channels. The failure to recognize a nonstationary river regime may also result in unsuccessful channelization.
Rapid channel incision has followed channelization of the main rivers of the Polish Carpathians in the 20th century. A case
study of the Raba River shows that incision has resulted from the increase in stream power caused by channelization and the
simultaneous reduction in sediment supply due to variations in basin management and a change in flood hydrographs. Calculations
of bedload transport in the river by the Meyer-Peter and Müller formula are shown to have resulted in unrealistic estimates,
perhaps because the different degree of bed armoring in particular cross-sections was neglected. It would have been possible
to avoid improper channelization if the decreasing trend in sediment load of the Carpathian rivers had been recognized on
the basis of geomorphological and sedimentological studies. Allowing the rivers to increase their sinuosity, wherever possible
without an erosional threat to property and infrastructure, and preventing further in-stream gravel mining are postulated
in order to arrest channel incision and reestablish the conditions for water and sediment storage on the floodplains. 相似文献
907.
Theoretical constructs, such as the river continuum concept, predict that the composition of benthic fauna in rivers will
be different from that of headwater streams. There exists a need to modify, for use on larger rivers, the bioassessment techniques
commonly used on small streams. Using aquatic macroinvertebrates and the “reference condition” approach, we developed and
tested a multimetric index for use on the rivers of Idaho. Reference sites were selected to represent the best current conditions
(i.e., least impacted) among Idaho rivers. The index performed well in distinguishing reference sites from sites displaying
some form of anthropogenic impairment. Individual metrics used in the index included: number of EPT taxa, total number of
taxa, percent dominant taxon, percent Elmidae, and percent predators. The index we developed for Idaho rivers was essentially
a modification of a framework designed for small streams, suggesting that techniques, including data analysis, currently used
for streams can be adapted for use on larger rivers. Adapting these methods for use in rivers is primarily a matter of (1)
selecting metrics relevant to the rivers of interest; (2) expanding the field sampling to encompass the greater habitat area
and, potentially, heterogeneity of rivers; and (3) selecting an appropriate form of data analysis. The approach we describe
here should be applicable to geographic regions other than Idaho. 相似文献
908.
Burger J Gochfeld M Powers CW Waishwell L Warren C Goldstein BD 《Environmental management》2001,27(4):501-514
In recent years there has been a startling rise in the issuance of fish consumption advisories. Unfortunately, compliance
by the public is often low. Low compliance can be due to a number of factors, including confusion over the meaning of advisories,
conflicting advisories issued by different agencies, controversies involving health benefits versus the risks from consuming
fish, and an unwillingness to act on the advisories because of personal beliefs. In some places, such as along the Savannah
River, one state (South Carolina) had issued a consumption advisory while the other (Georgia) had not, although at present,
both states now issue consumption advisories for the Savannah River. Herein we report on the development of a fish fact sheet
to address the confusing and conflicting information available to the public about consuming fish from the Savannah River.
The process involved interviewing fishers to ascertain fishing and consumption patterns, evaluating contaminant levels and
exposure pathways, discussing common grounds for the provision of information, and consensus-building among different regulatory
agencies (US Environmental Protection Agency, South Carolina Department of Health and Environmental Control, Georgia Department
of Natural Resources) and the Department of Energy. Consensus, a key ingredient in solving many different types of “commons”
problems, was aided by an outside organization, the Consortium for Risk Evaluation with Stakeholder Participation (CRESP).
The initial role for CRESP was to offer scientific data as a basis for groups with different assumptions about risks to reach
agreement on a regulatory response action. The process was an example of how credible science can be used to implement management
and policies and provide a basis for consensus-building on difficult risk communication issues. The paper provides several
lessons for improving the risk process from stakeholder conflicts, through risk assessment, to risk management. It also suggests
that consensus-building and risk communication are continuing processes that involve assimilation of new information on contaminants
and food-chain processes, state and federal law, public policy, and public response. 相似文献
909.
Identifying Influences on Model Uncertainty: An Application Using a Forest Carbon Budget Model 总被引:2,自引:0,他引:2
Uncertainty is an important consideration for both developers and users of environmental simulation models. Establishing quantitative
estimates of uncertainty for deterministic models can be difficult when the underlying bases for such information are scarce.
We demonstrate an application of probabilistic uncertainty analysis that provides for refinements in quantifying input uncertainty
even with little information. Uncertainties in forest carbon budget projections were examined with Monte Carlo analyses of
the model FORCARB. We identified model sensitivity to range, shape, and covariability among model probability density functions,
even under conditions of limited initial information. Distributional forms of probabilities were not as important as covariability
or ranges of values. Covariability among FORCARB model parameters emerged as a very influential component of uncertainty,
especially for estimates of average annual carbon flux. 相似文献
910.
Michaels S 《Environmental management》2001,27(1):27-35
Initiatives in the Neponset, Ipswich, and Sudbury-Assabet-Concord watersheds highlight how watershed-scale innovation in engaging
nongovernment participants is influenced, but not dominated, by the statewide program, the Massachusetts Watershed Initiative.
The presence or absence of three elements—external support, process, and issue—and the order in which they occur, shape the
viability of collaborative watershed-scale management initiatives. External support includes providing personnel or funding
from outside an initiative. Process is the interaction among individuals undertaking watershed-wide policy development and/or
implementation. An issue is an attention-requiring concern, vital to a watershed, that can most effectively be addressed by
a coordinated strategy among different parties. A process generated by an issue is sustainable and amenable to enhancement
through external support. The contribution of external support is most apparent when outside assistance is provided after
an issue has crystallized into clear problem needs that can be addressed through specific research projects or implementation
activities. Process is central in shaping issues, utilizing external support, and generating management results. The outcomes
of voluntary processes in the three watershed initiatives highlight how the evolution of the Massachusetts Watershed Initiative
leads to, and depends upon, the development of watershed-scale initiatives. 相似文献