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   295篇
  免费   3篇
  国内免费   6篇
安全科学   2篇
废物处理   13篇
环保管理   31篇
综合类   128篇
基础理论   45篇
环境理论   1篇
污染及防治   57篇
评价与监测   10篇
社会与环境   17篇
  2023年   2篇
  2022年   2篇
  2021年   7篇
  2020年   2篇
  2019年   8篇
  2018年   13篇
  2017年   8篇
  2016年   16篇
  2015年   8篇
  2014年   8篇
  2013年   15篇
  2012年   15篇
  2011年   21篇
  2010年   12篇
  2009年   15篇
  2008年   7篇
  2007年   13篇
  2006年   10篇
  2005年   3篇
  2004年   7篇
  2003年   7篇
  2002年   9篇
  2001年   4篇
  1999年   5篇
  1998年   3篇
  1996年   2篇
  1995年   3篇
  1994年   4篇
  1993年   3篇
  1987年   2篇
  1986年   2篇
  1984年   3篇
  1969年   2篇
  1966年   3篇
  1964年   4篇
  1963年   3篇
  1962年   3篇
  1961年   3篇
  1959年   2篇
  1958年   5篇
  1957年   6篇
  1956年   2篇
  1955年   4篇
  1953年   2篇
  1940年   2篇
  1926年   1篇
  1921年   2篇
  1920年   2篇
  1919年   1篇
  1915年   3篇
排序方式: 共有304条查询结果,搜索用时 15 毫秒
171.
Poor air quality is still a threat for human health in many parts of the world. In order to assess measures for emission reductions and improved air quality, three-dimensional atmospheric chemistry transport modeling systems are used in numerous research institutions and public authorities. These models need accurate emission data in appropriate spatial and temporal resolution as input. This paper reviews the most widely used emission inventories on global and regional scales and looks into the methods used to make the inventory data model ready. Shortcomings of using standard temporal profiles for each emission sector are discussed, and new methods to improve the spatiotemporal distribution of the emissions are presented. These methods are often neither top-down nor bottom-up approaches but can be seen as hybrid methods that use detailed information about the emission process to derive spatially varying temporal emission profiles. These profiles are subsequently used to distribute bulk emissions such as national totals on appropriate grids. The wide area of natural emissions is also summarized, and the calculation methods are described. Almost all types of natural emissions depend on meteorological information, which is why they are highly variable in time and space and frequently calculated within the chemistry transport models themselves. The paper closes with an outlook for new ways to improve model ready emission data, for example, by using external databases about road traffic flow or satellite data to determine actual land use or leaf area. In a world where emission patterns change rapidly, it seems appropriate to use new types of statistical and observational data to create detailed emission data sets and keep emission inventories up-to-date.

Implications: Emission data are probably the most important input for chemistry transport model (CTM) systems. They need to be provided in high spatial and temporal resolution and on a grid that is in agreement with the CTM grid. Simple methods to distribute the emissions in time and space need to be replaced by sophisticated emission models in order to improve the CTM results. New methods, e.g., for ammonia emissions, provide grid cell–dependent temporal profiles. In the future, large data fields from traffic observations or satellite observations could be used for more detailed emission data.  相似文献   

172.
The flaws of mainstream economic methodology are becoming widely acknowledged. Should we, therefore, reject all of its concepts within the quest for sustainability? A predicament looms: neither would it make sense to neglect useful tools, nor to redundantly replicate the mainstream’s narrow perspective on sustainability problems. We argue that avoiding both fallacies is possible because power of judgment facilitates non-dogmatic methodological decisions: the scientists’ judgment, that is, the capacity to apply general concepts to specific situations, supports their decisions concerning which methods are suitable for tackling a given sustainability problem. The intersubjective quality of judgment prevents the resulting methodological pluralism from drifting toward arbitrariness.  相似文献   
173.
In this paper, we develop a model to analyze the economics of carbon capture, transport, and storage (CCTS) in the wake of expected rising CO2 prices. We present a scalable mixed integer, multiperiod, welfare-optimizing network model for Europe, called CCTS-Mod. The model incorporates endogenous decisions on carbon capture, pipeline and storage investments, as well as capture, flow and injection quantities based on given costs, CO2 prices, storage capacities, and point source emissions. Given full information about future costs of CCTS-technology, and CO2 prices, the model determines a cost minimizing strategy on whether to purchase CO2 certificates, or to abate the CO2 through investments into a CCTS-chain on a site by site basis. We apply the model to analyze different scenarios for the deployment of CCTS in Europe, e.g., under high and low CO2 prices, respectively. We find that beyond CO2 prices of €50 per t, CCTS can contribute to the decarbonization of Europe’s industry sectors, as long as one assumes sufficient storage capacities (onshore and/or offshore). We find that CCTS is only viable for the power sector if the CO2 certificate price exceeds €75 per t.  相似文献   
174.
The fate of fullerene water suspension (FWS) in an aquatic system of Ceratophyllum sp., a rootless submerged plant, under non-sterile sediment-free conditions was investigated. Fast removal of FWS from water by the plants was observed and irreversible adsorption of C60 onto plants and increasing C60 mass on the plant surface with prolonged exposure durations were confirmed. An intact plant extraction procedure was developed and the majority (>80%) of C60 removed from water was extracted from the plants. C60 remained aggregated after being associated with the plants, which was verified by 13C NMR spectroscopy. Light micrographs showed association of FWS on and in the cuticle layers.  相似文献   
175.
In this article, we present a life cycle assessment (LCA) of CO2 capture and storage (CCS) for several lignite power plant technologies. The LCA includes post-combustion, pre-combustion and oxyfuel capture processes as well as subsequent pipeline transport and storage of the separated CO2 in a depleted gas field.The results show an increase in cumulative energy demand and a substantial decrease in greenhouse gas (GHG) emissions for all CO2 capture approaches in comparison with power plants without CCS, assuming negligible leakage within the time horizon under consideration. Leakage will, however, not be zero. Due to the energy penalty, CCS leads to additional production of CO2. However, the CO2 emissions occur at a much lower rate and are significantly delayed, thus leading to different, and most likely smaller, impacts compared to the no-sequestration case. In addition, a certain share of the CO2 will be captured permanently due to chemical reactions and physical trapping.For other environmental impact categories, the results depend strongly on the chosen technology and the details of the process. The post-combustion approach, which is closest to commercial application, leads to sharp increases in many categories of impacts, with the impacts in only one category, acidification, reduced. In comparison with a conventional power plant, the pre-combustion approach results in decreased impact in all categories. This is mainly due to the different power generation process (IGCC) which is coupled with the pre-combustion technology.In the case of the oxyfuel approach, the outcome of the LCA depends highly on two uncertain parameters: the energy demand for air separation and the feasibility of co-capture of pollutants other than CO2. If co-capture were possible, oxyfuel could lead to a near-zero emission power plant.  相似文献   
176.
During the last decade, forest certification has gained momentum as a market-based conservation strategy in tropical forest countries. Certification has been promoted to enhance forest management in countries where governance capacities are insufficient to adequately manage natural resources and enforce pertinent regulations, given that certification relies largely on non-governmental organisations and private businesses. However, at present there are few tropical countries with large areas of certified forests. In this study, we conducted semi-structured stakeholder interviews in Ecuador and Bolivia to identify key framework conditions that influence the costs and benefits for companies to switch from conventional to certified forestry operations. Bolivia has a much greater relative area under certified forest management than Ecuador and also significantly more certified producers. The difference in the success of certification between both countries is particularly notable because Bolivia is a poorer country with more widespread corruption, and is landlocked with less access to export routes. Despite these factors, several characteristics of the Bolivian forest industry contribute to lower additional costs of certified forest management compared to Ecuador. Bolivia has stronger government enforcement of forestry regulations a fact that increases the cost of illegal logging, management units are larger, and vertical integration in the process chain from timber extraction to markets is higher. Moreover, forestry laws in Bolivia are highly compatible with certification requirements, and the government provides significant tax benefits to certified producers. Results from this study suggest that certification can be successful in countries where governments have limited governance capacity. However, the economic incentives for certification do not only arise from favourable market conditions. Certification is likely to be more successful where governments enforce forestry laws, provide financial incentives for certified forestry, and provide land tenure security, and where large-scale and vertically integrated forestry operations are commercially feasible. For this reason, at present, there are few developing countries where forest certification is likely to achieve widespread success.  相似文献   
177.
The global animal food chain has a large contribution to the global anthropogenic greenhouse gas (GHG) emissions, but its share and sources vary highly across the world. However, the assessment of GHG emissions from livestock production is subject to various uncertainties, which have not yet been well quantified at large spatial scale. We assessed the uncertainties in the relations between animal production (milk, meat, egg) and the CO2, CH4, and N2O emissions in Africa, Latin America and the European Union, using the MITERRA-Global model. The uncertainties in model inputs were derived from time series of statistical data, literature review or expert knowledge. These model inputs and parameters were further divided into nine groups based on type of data and affected greenhouse gas. The final model output uncertainty and the uncertainty contribution of each group of model inputs to the uncertainty were quantified using a Monte Carlo approach, taking into account their spatial and cross-correlation. GHG emissions and their uncertainties were determined per livestock sector, per product and per emission source category. Results show large variation in the GHG emissions and their uncertainties for different continents, livestock sectors products or source categories. The uncertainty of total GHG emissions from livestock sectors is higher in Africa and Latin America than in the European Union. The uncertainty of CH4 emission is lower than that for N2O and CO2. Livestock parameters, CH4 emission factors and N emission factors contribute most to the uncertainty in the total model output. The reliability of GHG emissions from livestock sectors is relatively high (low uncertainty) at continental level, but could be lower at country level.  相似文献   
178.
Calls for more stakeholder participation and cooperation, the acknowledgement of uncertainties as well as for flexible and robust solutions have become frequent in the literature on climate change adaptation. Recent studies show that these calls are taken up only reluctantly in local adaptation compared to sectoral and technical solutions. The aim of this study is to examine to which extent adaptation as an embedded process within the local context allows for stakeholder participation, cooperation and the robustness and flexibility of adaptation measures. It applies an analytical approach, combining an action framework of adaptation and document-based discourse analysis, to assess both the procedural and the substantive viewpoint of an adaptation case in Finland. This twofold approach provides insight into how the adaptation process and content influence and condition each other. The analysis highlights how new approaches to adaptation have to compete with prevailing discourses and institutionalised practices, as public authorities take the dominant role in adaptation, striving for certain and safe solutions. This process has few participatory elements and leaves little leeway to address uncertainty.  相似文献   
179.
180.
Environmental threats and progressive degradation of natural resources are considered critical impediments to sustainable development. This paper reports on a participatory impact assessment of alternative soil and water conservation (SWC) scenarios in the Oum Zessar watershed, Tunisia. The first objective was to assess the impact of three SWC scenarios on key social, economic and environmental land use functions. The second objective was to test and evaluate the applicability of the 'Framework for Participatory Impact Assessment (FoPIA)' for assessing scenario impacts in the context of a developing country, in this case Tunisia. The assessed scenarios included: the originally planned SWC policy implementation at 85 % coverage of arable land of the watershed, the current implementation (70 %), and a hypothetical expansion of SWC measures to the entire watershed (100 %). Our results suggest that implementation of the SWC policy at 100 % coverage of arable land achieves the maximum socioeconomic benefit. However, if stakeholders' preferences regarding land use functions are taken into account, and considering the fact that the implementation of SWC measures also implies some negative changes to traditional landscapes and the natural system, SWC implementation at 85 % coverage of arable land might be preferable. The FoPIA approved to be a useful tool for conducting a holistic sustainability impact assessment of SWC scenarios and for studying the most intriguing sustainability problems while providing possible recommendations towards sustainable development. We conclude that participatory impact assessment contributes to an enhanced regional understanding of key linkages between policy effects and sustainable development, which provides the foundation for improved policy decision making.  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