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   293篇
  免费   2篇
安全科学   16篇
废物处理   11篇
环保管理   31篇
综合类   47篇
基础理论   68篇
污染及防治   96篇
评价与监测   10篇
社会与环境   13篇
灾害及防治   3篇
  2022年   3篇
  2021年   3篇
  2020年   9篇
  2019年   3篇
  2018年   1篇
  2017年   7篇
  2016年   14篇
  2015年   10篇
  2014年   16篇
  2013年   14篇
  2012年   14篇
  2011年   31篇
  2010年   18篇
  2009年   17篇
  2008年   13篇
  2007年   21篇
  2006年   20篇
  2005年   18篇
  2004年   17篇
  2003年   3篇
  2002年   6篇
  2001年   3篇
  1999年   4篇
  1998年   3篇
  1997年   2篇
  1995年   3篇
  1994年   3篇
  1993年   1篇
  1992年   4篇
  1991年   1篇
  1990年   4篇
  1989年   1篇
  1987年   1篇
  1986年   3篇
  1984年   1篇
  1983年   1篇
  1977年   1篇
  1960年   1篇
排序方式: 共有295条查询结果,搜索用时 31 毫秒
251.
Reconnecting to the Biosphere   总被引:3,自引:0,他引:3  
Humanity has emerged as a major force in the operation of the biosphere, with a significant imprint on the Earth System, challenging social-ecological resilience. This new situation calls for a fundamental shift in perspectives, world views, and institutions. Human development and progress must be reconnected to the capacity of the biosphere and essential ecosystem services to be sustained. Governance challenges include a highly interconnected and faster world, cascading social-ecological interactions and planetary boundaries that create vulnerabilities but also opportunities for social-ecological change and transformation. Tipping points and thresholds highlight the importance of understanding and managing resilience. New modes of flexible governance are emerging. A central challenge is to reconnect these efforts to the changing preconditions for societal development as active stewards of the Earth System. We suggest that the Millennium Development Goals need to be reframed in such a planetary stewardship context combined with a call for a new social contract on global sustainability. The ongoing mind shift in human relations with Earth and its boundaries provides exciting opportunities for societal development in collaboration with the biosphere--a global sustainability agenda for humanity.  相似文献   
252.
Modeling thermoelectric power generation in view of climate change   总被引:1,自引:0,他引:1  
In this study we investigate how thermal power plants with once-through cooling could be affected by future climate change impacts on river water temperatures and stream flow. We introduce a model of a steam turbine power plant with once-through cooling at a river site and simulate how its production could be constrained in scenarios ranging from a one degree to a five degree increase of river temperature and a 10–50% decrease of stream flow. We apply the model to simulate a large nuclear power plant in Central Europe. We calculate annual average load reductions, which can be up to 11.8%, assuming unchanged stream flow, which leads to average annual income losses of up to 80 million €. Considering simultaneous changes in stream flow will exacerbate the problem and may increase average annual costs to 111 million € in a worst-case scenario. The model demonstrates that power generation could be severely constrained by typical climate impacts, such as increasing river temperatures and decreasing stream flow.  相似文献   
253.
The input of acidity to Swedish forest soils through forestry between 1955 and 2010 is compared with the acid input from atmospheric deposition. Depending on region, input of acidity from forestry was the minor part (25–45%) of the study period’s accumulated acid input but is now the dominating source (140–270 molc ha−1 year−1). The net uptake of cations due to the increase in standing forest biomass, ranged between 35 and 45% of the forestry related input of acidity while whole-tree harvesting, introduced in the late 1990s, contributed only marginally (< 2%). The geographical gradient in acid input is reflected in the proportion of acidified soils in Sweden but edaphic properties contribute to variations in acidification sensitivity. It is important to consider the acid input due to increases in standing forest biomass in acidification assessments since it is long-term and quantitatively important.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01540-y.  相似文献   
254.
Over the past few decades, four distinct and largely independent research and policy communities--disaster risk reduction, climate change adaptation, environmental management and poverty reduction--have been actively engaged in reducing socio-economic vulnerability to natural hazards. However, despite the significant efforts of these communities, the vulnerability of many individuals and communities to natural hazards continues to increase considerably. In particular, it is hydro-meteorological hazards that affect an increasing number of people and cause increasingly large economic losses. Arising from the realisation that these four communities have been largely working in isolation and enjoyed only limited success in reducing vulnerability, there is an emerging perceived need to strengthen significantly collaboration and to facilitate learning and information exchange between them. This article examines key communalities and differences between the climate change adaptation and disaster risk reduction communities, and proposes three exercises that would help to structure a multi-community dialogue and learning process.  相似文献   
255.
Jansson A  Colding J 《Ambio》2007,36(8):650-656
Urban dwellers depend on the generation of ecosystem services for their welfare. The city of Stockholm is growing, and a 25% increase in population is projected by 2030. The effects of urban development were estimated through the quantification of nitrogen (N) leakage to the Baltic Sea under two urban development scenarios. We found that total net N load will increase by 6% or 8%, depending on which growth scenario is applied, and population increase by itself will contribute at least 15% of the point source N leakage. Technical improvements in sewage treatment could, according to our results, decrease total N load to the Baltic Sea by 4%. Based on our results, we conclude that proactive measures such as spatial urban planning can provide a constructive tool for sustainable urban development on regional as well as national and international scales, depending on geographical context as well as the ecosystem services' scale of operation.  相似文献   
256.
257.
Mixing inside an anaerobic digester is often continuous and is not actively controlled. The selected mixing regime can however affect both gas production and the energy efficiency of the biogas plant. This study aims to evaluate these effects and compare three different mixing regimes, 150 RPM and 25 RPM continuous mixing and minimally intermittent mixing for both digestion of fresh substrate and post-digestion of the organic fraction of municipal solid waste. The results show that a lower mixing intensity leads to a higher biogas production rate and higher total biogas production in both cases. 25 RPM continuous mixing and minimally intermittent mixing resulted in similar biogas production after process stabilization, while 150 RPM continuous mixing resulted in lower production throughout the experiment. The lower gas production at 150 RPM could not be explained by the inhibition of volatile fatty acids. Cumulative biogas production until day 31 was 295 ± 2.9, 317 ± 1.9 and 304 ± 2.8 N ml/g VS added during digestion of fresh feed and 113 ± 1.3, 134 ± 1.1 and 130 ± 2.3 N ml/g VS added during post digestion for the 150 RPM, 25 RPM and minimally mixed intensities respectively. As well as increasing gas production, optimal mixing can improve the energy efficiency of the anaerobic digestion process.  相似文献   
258.
The landscape-level and multiscale biodiversity monitoring program National Inventory of Landscapes in Sweden (NILS) was launched in 2003. NILS is conducted as a sample-based stratified inventory that acquires data across several spatial scales, which is accomplished by combining aerial photo interpretation with field inventory. A total of 631 sample units are distributed across the land base of Sweden, of which 20% are surveyed each year. By 2007 NILS completed the first 5-year inventory phase. As the reinventory in the second 5-year phase (2008?C2012) proceeds, experiences and insights accumulate and reflections are made on the setup and accomplishment of the monitoring scheme. In this article, the emphasis is placed on background, scope, objectives, design, and experiences of the NILS program. The main objective to collect data for and perform analyses of natural landscape changes, degree of anthropogenic impact, prerequisites for natural biological diversity and ecological processes at landscape scale. Different environmental conditions that can have direct or indirect effects on biological diversity are monitored. The program provides data for national and international policy and offers an infrastructure for other monitoring program and research projects. NILS has attracted significant national and international interest during its relatively short time of existence; the number of stakeholders and cooperation partners steadily increases. This is constructive and strengthens the incentive for the multiscale monitoring approach.  相似文献   
259.
260.
The urban fringe has been described as 'planning's last frontier'; a zone of transition and interface between town and country where a broad variety of land uses and activities come together, and where development pressure is often intense. In this paper, we argue that the urban fringe possesses special characteristics, making it more than simply a transitional landscape. These characteristics centre on patterns of land use, biodiversity and leisure/development opportunity which are unique to the urban edge and to land extending away from built-up areas. The uniqueness, diversity and particular dynamics of the urban fringe demands a special brand of planning and management response. Therefore we suggest that the principle of 'multi-functionality' provides a framework for action, showing how diversity can be managed and supported. Through brief case studies, we demonstrate how functional interactions at the urban fringe might be promoted in the future.  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