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   252篇
  免费   15篇
  国内免费   2篇
安全科学   20篇
废物处理   5篇
环保管理   117篇
综合类   44篇
基础理论   51篇
污染及防治   6篇
评价与监测   4篇
社会与环境   18篇
灾害及防治   4篇
  2023年   3篇
  2022年   2篇
  2021年   1篇
  2020年   3篇
  2019年   5篇
  2018年   1篇
  2017年   13篇
  2016年   13篇
  2015年   5篇
  2014年   5篇
  2013年   14篇
  2012年   16篇
  2011年   10篇
  2010年   8篇
  2009年   24篇
  2008年   14篇
  2007年   13篇
  2006年   8篇
  2005年   9篇
  2004年   9篇
  2003年   10篇
  2002年   7篇
  2001年   10篇
  2000年   5篇
  1999年   7篇
  1998年   6篇
  1997年   4篇
  1996年   1篇
  1995年   3篇
  1994年   2篇
  1993年   3篇
  1992年   1篇
  1990年   4篇
  1985年   1篇
  1984年   4篇
  1981年   4篇
  1980年   1篇
  1979年   6篇
  1978年   3篇
  1977年   2篇
  1976年   1篇
  1974年   2篇
  1972年   2篇
  1971年   4篇
排序方式: 共有269条查询结果,搜索用时 504 毫秒
121.
The article quantifies the size of ‘hidden’ social costs that are incurred by forestry offsets in the voluntary market that promise to offset present emissions sometime in the future. It does this by estimating the difference between the social costs of carbon (C) emitted and of costs offset by removal of C from the atmosphere by reforestation/afforestation. All current attempts to make forestry offsets more reliable focus on quality control rather than the mismatch of the timing of emissions and their offset. Recommendations that follow from the analysis are twofold. First, that markets for carbon dioxide equivalent (CO2e) removals by voluntary offsets should be confined to the annual incremental removals actually achieved. Second, the promoters of voluntary offsets projects should declare the annual stream of carbon credits and debits expected so that buyers can place a present value on such projects.  相似文献   
122.
Changing public attitudes and behaviour is key to achieving the UK target of a 60% reduction in carbon dioxide emissions by 2050. Top-down campaigns that have provided information to a passive public have not necessarily resulted in pro-environmental behavioural change. This paper examines the use of a personalised social marketing approach to engage the public in changing their personal travel. It provides the results of a project in the City of York to foster voluntary travel behavioural change. Using face-to-face discussions, personalised information and incentives, a statistically significant reduction in car use and an increase in cycling and the use of public transport were achieved over a six-month period. However, this change was not sustained 12 months later. The paper explores the contrasting perspectives on behavioural change and examines the possible lessons that can be learnt to foster voluntary behavioural change in other aspects of household consumption.  相似文献   
123.
This paper aims to practically contribute to the literature on the use of cost–benefit analysis (CBA) and economic evaluation in environmental decision-making through a practical case study: the implementation of the Water Framework Directive (WFD) in France, for the first cycle (2010–2015). The WFD requires that Member States achieve “good status” for all water bodies in 2015. However, exemptions can apply, if justified, on natural, technical or economic reasons. For the latter, EU guidance documents recommend to use CBA. In France, the water agencies carried out 710 CBAs on proposed restoration projects for water bodies. This article reports on this experience. Issues concerning these analyses are discussed, especially the assessment of non-market benefits. Finally, this article questions the use of economic analysis in the implementation of environmental policy.  相似文献   
124.
The Paris Agreement reached during the COP21 in December 2015 represents a timid step towards burden sharing in emission mitigation involving all countries. However, given the heterogeneity of countries and their relative differences in vulnerability to climate change damage and in mitigation costs, compensating schemes are required to reach an effective agreement. This paper investigates the role of the Green Climate Fund (GCF) as a potential compensating measure for both adaptation and mitigation actions under a global climate regime. A dynamic climate-economy computable general equilibrium model (GDynEP) is developed by including both a monetary valuation of climate change damage costs and two alternative methods to determine the allocation of GCF resources among receiving countries and between adaptation and mitigation contributions. Results show that, despite the high costs associated with the implementation of mitigation actions, most developing countries would face even higher costs in case of inaction. Furthermore, the preference of a country for an allocation method is strongly influenced by its characteristics and needs. Consequently, a main policy conclusion is to design country-specific sharing rules for GCF in order to maximize country participation in a global agreement.  相似文献   
125.
The objective of this study is to estimate the vehicle kilometer traveled (VKT) and on-road emissions using the traffic volume in urban. We estimated two VKT; one is based on registered vehicles and the other is based on traffic volumes. VKT for registered vehicles was 2.11 times greater than that of the applied traffic volumes because each VKT estimation method is different. Therefore, we had to define the inner VKT is moved VKT inner in urban to compare two values. Also, we focused on freight modes because these are discharged much air pollutant emissions. From analysis results, we found middle and large trucks registered in other regions traveled to target city in order to carry freight, target city has included many industrial and logistics areas. Freight is transferred through the harbors, large logistics centers, or via locations before being moved to the final destination. During this process, most freight is moved by middle and large trucks, and trailers rather than small trucks for freight import and export. Therefore, these trucks from other areas are inflow more than registered vehicles. Most emissions from diesel trucks had been overestimated in comparison to VKT from applied traffic volumes in target city. From these findings, VKT is essential based on traffic volume and travel speed on road links in order to estimate accurately the emissions of diesel trucks in target city. Our findings support the estimation of the effect of on-road emissions on urban air quality in Korea.  相似文献   
126.
环境成本内部化是协调人地关系发展的必然要求,是实现可持续发展的重要手段.从东北地区生态环境问题的现状入手,利用环境经济学中的环境成本论对其形成机理进行分析,结合生态环境问题产生的根源、区域生态环境建设的重要性以及实施的可行性,在东北老工业基地改造振兴的背景下,提出东北老工业基地环境建设的战略着眼点.  相似文献   
127.
飞机作为航空产品,使用维护成本在全寿命周期费用中占据了相当大的比例。将使用维护成本折算为备件的采购和维修成本,在设计阶段通过基于备件的分析,分类计算在不同飞行强度下各种备件的采购和维修费用,从而确定飞机在满足用户需求的前提下所能执行的最经济的飞行强度。以某型飞机为例,提出了一种最经济飞行强度的计算方法,有助于在设计阶段规划飞机的使用和维护保障。  相似文献   
128.
IntroductionDriving is important for well-being among older adults, but age-related conditions are associated with driving reduction or cessation and increased crash risk for older drivers. Our objectives were to describe population-based rates of older drivers’ licensing and per-driver rates of crashes and moving violations.Methods: We examined individual-level statewide driver licensing, crash, and traffic citation data among all New Jersey drivers aged ≥ 65 and a 35- to 54-year-old comparison group during 2010–2014. Rate ratios (RR) of crashes and moving violations were estimated using Poisson regression.Results: Overall, 86% of males and 71% of females aged ≥ 65 held a valid driver’s license. Older drivers had 27% lower per-driver crash rates than middle-aged drivers (RR: 0.73, 95% CI: 0.73, 0.74)—with appreciable differences by sex—but 40% higher fatal crash rates (RR: 1.40 [1.24, 1.58]). Moving violation rates among older drivers were 72% lower than middle-aged drivers (RR: 0.28 [0.28, 0.28]).Conclusion: The majority of older adults are licensed, with substantial variation by age and sex. Older drivers have higher rates of fatal crashes but lower rates of moving violations compared with middle-aged drivers.Practical applications: Future research is needed to understand the extent to which older adults drive and to identify opportunities to further reduce risk of crashes and resultant injuries among older adults.  相似文献   
129.
董雪旺  张捷  章锦河 《自然资源学报》2011,26(11):1983-1997
旅行费用法(TCM)是一种基于观测资料评估旅游资源价值的显示偏好法。论文在文献梳理的基础上,对TCM研究过程中的偏差进行了述评,并指出了可能的解决方案;然后,讨论了TCM的有效性、适用性以及合法性,并提出进一步研究的重点和方向。文献综述表明:常见的TCM模型可以分为ZTCM、TCIA、GTCM、ITCM、HTCM和RUM六种类型,在研究中应根据实际情况选择合适的模型;旅行费用测度中的内生分层、抽样误差、时间的机会成本计算、多目的地之间的费用分成等问题,需求函数估算中的多重共线性、内生性、函数形式的选择等问题,均会导致评估结果出现偏差;TCM在发展中国家的有效性、适用性和合法性遭到了质疑,但仍不失为一种评估旅游资源价值的有效手段;今后的研究要加强TCM中的偏差分析及有效性检验,并着力于模型的修正和改进,加强TCM与CVM的结合,提高研究方法的有效性。  相似文献   
130.
Faced with an intermittent but potent threat, animals exhibit behavior that allows them to balance foraging needs and avoid predators and over time, these behaviors can become hard-wired adaptations with both species trying to maximize their own fitness. In systems where both predator and prey share similar sensory modalities and cognitive abilities, such as with marine mammals, the dynamic nature of predator-prey interactions is poorly understood. The costs and benefits of these anti-predator adaptations need to be evaluated and quantified based on the dynamic engagement of predator and prey. Many theoretic models have addressed the complexity of predator-prey relationships, but few have translated into testable mechanistic models. In this study, we developed a spatially-explicit, geo-referenced, individual-based model of a prototypical adult dusky dolphin off Kaikoura, New Zealand facing a more powerful, yet infrequent predator, the killer whale. We were interested in two primary objectives, (1) to capture the varying behavioral game between a clever prey and clever predator based on our current understanding of the Kaikoura system, (2) to compare evolutionary costs vs. benefits (foraging time and number of predator encounters) for an adult non-maternal dusky dolphin at various levels of killer whale-avoidance behaviors and no avoidance rules. We conducted Monte Carlo simulations to address model performance and parametric uncertainty. Mantel tests revealed an 88% correlation (426 × 426 distance matrix, km2) between observed field sightings of dusky dolphins with model generated sightings for non-maternal adult dusky dolphin groups. Simulation results indicated that dusky dolphins incur a 2.7% loss in feeding time by evolving the anti-predator behavior of moving to and from the feeding grounds. Further, each evolutionary strategy we explored resulted in dolphins incurring an additional loss of foraging time. At low killer whale densities (appearing less than once every 3 days), each evolutionary strategy simulated converged towards the evolutionary cost of foraging, that is, the loss in foraging time approached the 2.7% loss experienced by evolving near shore-offshore movement behavior. However, the highest level of killer whale presence resulted in 38% decreases in foraging time. The biological significance of these losses potentially incurred by a dusky dolphin is dependent on various factors from dolphin group foraging behavior and individual energy needs to dolphin prey availability and behavior.  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