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   4561篇
  免费   136篇
  国内免费   107篇
安全科学   199篇
废物处理   41篇
环保管理   1114篇
综合类   1939篇
基础理论   312篇
环境理论   20篇
污染及防治   319篇
评价与监测   624篇
社会与环境   202篇
灾害及防治   34篇
  2023年   26篇
  2022年   41篇
  2021年   58篇
  2020年   163篇
  2019年   64篇
  2018年   60篇
  2017年   119篇
  2016年   143篇
  2015年   104篇
  2014年   183篇
  2013年   231篇
  2012年   172篇
  2011年   320篇
  2010年   163篇
  2009年   286篇
  2008年   223篇
  2007年   231篇
  2006年   225篇
  2005年   114篇
  2004年   135篇
  2003年   190篇
  2002年   178篇
  2001年   181篇
  2000年   199篇
  1999年   173篇
  1998年   149篇
  1997年   148篇
  1996年   89篇
  1995年   65篇
  1994年   79篇
  1993年   75篇
  1992年   51篇
  1991年   30篇
  1990年   15篇
  1989年   18篇
  1988年   10篇
  1987年   8篇
  1986年   16篇
  1985年   14篇
  1984年   14篇
  1983年   6篇
  1982年   7篇
  1981年   6篇
  1980年   4篇
  1978年   11篇
  1977年   5篇
  1974年   1篇
  1969年   1篇
排序方式: 共有4804条查询结果,搜索用时 203 毫秒
621.
622.
Incineration is the main option for residual Municipal Solid Waste treatment in France. This study compares the environmental performances of 110 French incinerators (i.e. 85% of the total number of plants currently in activity in France) in a Life Cycle Assessment perspective, considering 5 non-toxic impact categories: climate change, photochemical oxidant formation, particulate matter formation, terrestrial acidification and marine eutrophication. Mean, median and lower/upper impact potentials are determined considering the incineration of 1 tonne of French residual Municipal Solid Waste. The results highlight the relatively large variability of the impact potentials as a function of the plant technical performances. In particular, the climate change impact potential of the incineration of 1 tonne of waste ranges from a benefit of ?58 kg CO2-eq to a relatively large burden of 408 kg CO2-eq, with 294 kg CO2-eq as the average impact. Two main plant-specific parameters drive the impact potentials regarding the 5 non-toxic impact categories under study: the energy recovery and delivery rate and the NOx process-specific emissions. The variability of the impact potentials as a function of incinerator characteristics therefore calls for the use of site-specific data when required by the LCA goal and scope definition phase, in particular when the study focuses on a specific incinerator or on a local waste management plan, and when these data are available.  相似文献   
623.
Alfalfa is the major forage crop produced in temperate regions worlwide. Although this crop is currently used mainly for producing high-value livestock feed, its application for bioenergy production is a recent focus of interest. Even though it is not mandatory, alfalfa is normally dried in order to improve the quality of the final product. In this study, Life Cycle Assessment (LCA) was used to quantify the environmental impacts linked to alfalfa production in the major cultivation zone in Spain (Ebro Valley), including field activities, dehydration and transport to farms for livestock feeding. In addition, the identification of the most relevant processes contributing to the environmental impact and the potential improvements actions were also defined as objectives. Inventory data were obtained mainly from interviews with farmers complemented with published literature and comments from experts.LCA results were obtained for global warming, acidification, eutrophication, photochemical oxidant formation, land use, non-renewable cumulative energy demand and human, terrestrial and aquatic ecotoxicities. Within the life cycle of alfalfa, the dehydration process, production of phosphate fertilizer, application of nitrogen fertilizers and pesticides, water consumption and final transport to the consumer (by road and ship) were identified as hot spots. Based on these, some improvement measures were proposed and evaluated: (i) reduction of the moisture content of alfalfa and the use of a higher percentage of biomass for combustion in the dehydration process, (ii) no application of nitrogen fertilizer in maintenance years and (iii) use of more efficient trucks for transport. Their implementation would produce significant reduction of eutrophication, global warming, acidification, non-renewable cumulative energy demand and, to a lesser extent, photochemical oxidation formation and human toxicity impacts.  相似文献   
624.
This article examines the framing of environmental risks and natural disasters in factual entertainment television programs of the early 2000s, a hybrid form combining techniques from documentary with techniques such as dramatic reconstructions and computer-generated imagery from entertainment genres. Using qualitative frame analysis, it examines a range of factual entertainment television programs' framing of environmental risk and natural disasters in terms of their attitudes, representation of human participants and visual composition. The article considers the similarities and differences in the framing of natural disasters as factual entertainment compared to the framing of natural disasters in news, documentary and fiction film. It argues that such programs offer representational frames both consonant with and distinct from other media and concludes that they problematically offer a predominantly fatalistic response to environmental risk, constructing natural disasters as voyeuristic spectacles for vicarious entertainment.  相似文献   
625.
As resource conservation is an imperative for sustainable development, it is crucial to achieve a deeper understanding of the factors involved in people's decisions to recycle. This is even more so because the level of environmental concern is usually higher than the level of ecological behaviours. In this paper we take this fact as indicating that decision-making regarding conservation behaviours happens in the context of an internal debate where contradictory ideas are weighed up and the possibility of ambivalence arises. The main aim of this paper is therefore to explore how contradiction and ambivalence impact upon the attitudes, intentions and pro-ecological behaviours of the private sphere. The paper focuses specifically on the separation and deposition of metal cans, and compares the predictive capacity of beliefs, attitudes and intentions for two groups of respondents – one with a high and another with a low level of ambivalence, as assessed with a direct measure. The role of personal identity and the influence of structural constraints are also explored. Results demonstrate a clear moderating effect of experienced ambivalence, and show how beliefs, particularly negative ones, present a higher predictive capacity of the attitude in the high-ambivalence group, and personal identity plays a relevant role in predicting behaviour in both groups. We discuss the importance of pursuing the study of ambivalence when analysing decision-making in the conservation area.  相似文献   
626.
介绍了龙江县境内的江河流域、泡沼、泉沟及水利工程概况。提出了对一、二、三类河流的水环境保护,水库的改造与利用,泡沼水域的涵养和利用。并提出了相应的保障措施。  相似文献   
627.
/ This study examines similarities and differences between organic and conventional farmers. We explore the factors that underlie farmers' conservation attitudes and behaviors, including demographic and farm characteristics, awareness of and concern for environmental problems associated with agriculture, economic orientation toward farming, and self-reported conservation practices. A series of intensive personal interviews was conducted with 25 farmers in Washtenaw County, Michigan, USA, using both qualitative and quantitative survey methods. The findings indicate that both groups of farmers share a concern for the economic risks associated with farming, although the organic farmers reported a significantly greater concern for long-term sustainability and a greater willingness to incur present risk to gain future benefits. Organic farmers expressed a greater awareness of and concern for environmental problems associated with agriculture. Organic farmers also scored significantly higher on a multifaceted measure of conservation practices, although both groups had a fairly high adoption rate. Implications of these findings are discussed, relative to economic risks of farming, implications for new farmers, effectiveness of conservation education and government programs, and impact of farm size and crop diversity.KEY WORDS: Environmental attitudes; Conservation behaviors; Organic farming; Agricultural sustainability  相似文献   
628.
The concentration of a large spectrum of environmental contaminants (PCBs, PAHs, pesticides and metals) was assessed in surface sediments of two Ligurian harbours (Sanremo and Alassio, NW Mediterranean Sea, Italy) and their relative impact on micro-meiobenthic assemblages was analysed. Concentration, distribution and relative importance of the different contaminants varied considerably between harbours in relation to the different anthropic activities and contamination sources. Results from Principal Component Analysis indicated that high levels of contaminants were typically correlated with low micro-meiobenthic abundance in the sediment. Heavy metals and the organic enrichment were the main factors affecting the distribution and abundance of the bacterial and meiofaunal assemblages in Alassio harbour, whereas hydrocarbons and pesticides played a major role in Sanremo sediments. Neither the bacteria density nor the meiofauna abundance were dependent on sediment grain size, suggesting that micro-meiobenthic parameters may be under the influence of other variables. Our results suggest that high concentrations of contaminants independently from their source or typology are responsible for the impact observed on micro-meiobenthic assemblages in these harbours.  相似文献   
629.
/ A number of strategies for the control of vehicular emissions are being considered by the Philippine government to address Metropolitan Manila's air quality problem. An analytical tool is needed for optimizing criteria pollutant reductions given the budgetary constraints. The simplest approach is to take costs and pollutant removals to be linear with each strategy's scale of activity, and this is readily solved as a linear programming problem. Another approach is to use a dynamic system of weights which shift with progressive improvements in pollutant emissions. The two approaches yield somewhat different results, suggesting the sensitivity of the solution to the assumed weights. The study also illustrates the importance of a sound methodology for evaluating priorities given to different air quality goals. One such methodology may involve a polling of expert panels and the public to gain insight into the relative importance given to competing emissions reduction goals. An informal polling of resource agency staff was conducted and discussed in this paper. The authors take the position that proper planning involves tracing intermediate steps to the final outcome and not just focusing on the latter.KEY WORDS: Vehicular emissions; Urban air quality; Emissions control; Optimization; Manila; Environmental systems analysis  相似文献   
630.
This paper analyses the environmentally-induced migration and displacement resulting from L’Aquila's earthquake of 2009. After a general critical overview of the social science literature on this topic, the main changes in the migration system are analysed looking at the roots and trajectories of the forced human displacement that followed the earthquake, and reflecting on the challenges related to post-earthquake demographic movements and post-disaster resettlement. Through the analysis of the pre disaster (2002–2008) and recovery period (2009–2013) data, this paper offers a general model of how environmental disaster might affect migration and displacement and suggests the main challenges related to the post-disaster governance. Relying on ISTAT data on internal migration in Italy this paper argues that the post-seismic recovery period is characterized by a strong increase of out-flows from L’Aquila to other provinces, within the Abruzzo region and outside it, in particular toward the closest regions (Latium, Campania).  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