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   381篇
  免费   7篇
  国内免费   2篇
安全科学   15篇
废物处理   7篇
环保管理   163篇
综合类   122篇
基础理论   30篇
环境理论   4篇
污染及防治   25篇
评价与监测   7篇
社会与环境   16篇
灾害及防治   1篇
  2023年   1篇
  2022年   5篇
  2021年   10篇
  2020年   10篇
  2019年   11篇
  2018年   2篇
  2017年   24篇
  2016年   26篇
  2015年   18篇
  2014年   14篇
  2013年   16篇
  2012年   3篇
  2011年   30篇
  2010年   7篇
  2009年   29篇
  2008年   22篇
  2007年   17篇
  2006年   16篇
  2005年   12篇
  2004年   9篇
  2003年   8篇
  2002年   10篇
  2001年   13篇
  2000年   9篇
  1999年   5篇
  1998年   4篇
  1997年   7篇
  1996年   7篇
  1995年   4篇
  1994年   5篇
  1993年   4篇
  1992年   1篇
  1991年   4篇
  1990年   3篇
  1989年   4篇
  1988年   2篇
  1987年   1篇
  1986年   2篇
  1985年   3篇
  1984年   3篇
  1983年   2篇
  1982年   4篇
  1980年   2篇
  1979年   1篇
排序方式: 共有390条查询结果,搜索用时 31 毫秒
161.
Land degradation in the Ethiopian highlands is considered to be one of the major problems threatening agricultural development and food security in the country. However, knowledge about the forces driving the long-term dynamics in land resources use is limited. This research integrates biophysical information with socio-economic processes and policy changes to examine the dynamics of land resource use and farmers' livelihoods in the Beressa watershed for over 40 years during the second half of the 20th century. It was found that there have been substantial dynamics in land resource use in the area. The natural vegetation cover has been extensively cleared, although most of the cleared areas have since been replaced with plantations. Grazing land has expanded remarkably at the expense of cropland and bare land. However, the expansion of cropland was minimal over the 43-year period despite a quadrupling of the population density. Yields have not increased to compensate for the reduction in per capita cropland, and the soil quality appears to be not that good. Though the farmers perceived it otherwise, the long-term rainfall pattern has improved. In response to soil degradation, water shortage, socio-economic and policy changes, farmers have tended to gradually change from annual cropping to tree planting and livestock production to cope with the problems of soil degradation, water scarcity and smaller farms. Income diversification through the sale of wood and cattle dung is becoming a major livelihood strategy. Apparently, however, little attention has been paid to investments in soil and water conservation (SWC) and local soil fertility amendments. In particular, increased erosion and related high nutrient losses in sediments, as well as the removal of potentially available soil nutrients through the sale of manure threatens to damage agricultural sustainability in the area.  相似文献   
162.
This paper investigates how the notion of ‘sustainability’ is strategically framed in the context of Dutch infrastructure governance in the Netherlands. By conducting a frame analysis (based on policy documents, websites and semi-structured interviews), the paper discerns six sustainability frames. These frames concern substantive (e.g., more focus on ecology), process (activating new networks) and organizational (e.g., new practices of work) aspects. The paper also illustrates how these sustainability frames relate to the changing institutional context of infrastructure policy and governance more broadly. The paper discusses some of the productive and challenging implications of the dynamics of sustainability in today’s complex and multi-dimensional world of governance.  相似文献   
163.
The three basic principles of sustainable development, relating to ecology, economy and society, have long been embedded within national and international strategies. In recent years we have augmented these principles by a further seven considerations giving rise to the so-called 10-tenets of sustainable management. Whilst theoretically appealing, discussion of the tenets to date has been largely generic and qualitative and, until the present paper, there has been no formal and quantitative application of these tenets to an actual example. To promote the concept of successful and sustainable environmental management there is the need to develop a robust and practical framework to accommodate value judgements relating to each of the tenets. Although, as originally presented, the tenets relate specifically to management measures, they may also be applied directly to a specific development or activity. This paper examines the application of the tenets in both of these contexts, and considers their incorporation into an assessment tool to help visualise and quantify issues of sustainability.  相似文献   
164.
The National Water Commission (NWC) and the $2 billion Australian Government Water Fund (the fund) has drawn attention to the need for innovative and adaptive practices for water use. The NWC and the fund, whilst a critical and catalytic step in the recognition of the current water situation in Australia, has thus far neglected to consider the systemic failures of the water, irrigation and related industries that led to this point. The underlying issue of the efficient allocation of water resources can be resolved by the harmonisation of competing demands (economic, social and environmental) and the establishment of governance structures to reduce institutional impediments. The linking of the fund to National Competition Council (NCC) payments is an important consideration in this process. This paper will argue that governance reform and institutional (re)alignment to remedy the impediments to the efficient allocation of water resources needs to be embedded in and linked to national competition policy principles. This paper will consider the NWC in this context with the aim of informing future policy to consider the systemic failures of the water industry and to forge institutional change for the more effective allocation of water.  相似文献   
165.
The increase in the number of heavy duty vehicles (HDV) is inherently accompanied by increase in congestion, pollutant emissions and energy use as well as infrastructure overuse, all of which have broad societal implications. In addition to affecting the environment, contributing markedly to global warming, significant implications for the health of many residents living along traffic corridors as well as increases in the cost of infrastructure maintenance are logical consequences. In this interdisciplinary work a holistic approach is presented for the assessment of the combined effects of HDV employing pollutant emissions, noise and dynamic load of vehicles as criteria. Results show that vehicles that are environmentally friendly due to their pollutant emissions are not necessarily environmentally friendly when their noise emissions are considered. Each relevant parameter has to be assessed individually. Using a proposed model, the parameters are combined to obtain a holistic impression of the vehicles’ total environmental footprint. This information can be used by policy makers to introduce a bonus/malus system that would encourage vehicles with a total low environmental footprint using the “polluter/user pays” principle.  相似文献   
166.
To address increasing climatic variability and extremes, cities are gradually forced to develop climate change adaptation strategies that can ensure a continuous and transformative adaptation process. There is widespread consensus that the sustainable establishment of such strategies requires transdisciplinary approaches, that is, the involvement of internal and external stakeholders (state, civil society and market actors) to become part of the change and find innovative ways to unite their efforts and capacities. However, there is little research and hardly any empirical evidence on the process of stakeholder involvement and co-production in the development of municipal adaptation strategies. Against this background, this paper examines the factors that influence how and why different stakeholders are involved (or excluded) during the processes of developing adaptation strategies, and how this gets reflected in process outcomes. Based on applied participatory analysis of two pioneering municipalities in Germany and Sweden, the paper identifies and contrasts existing patterns to feed back into both theory and practice. Synergies, mismatches, barriers and driving forces for adaptation co-production are identified and contrasted with current adaptation discourses. The results highlight how the level of internal and external stakeholder involvement is conditional on (changes in) the broader governance context, and the associated power constellations in which stakeholders act (e.g., standing of departments, proximity to the decision-making body, changes in [or constellations of] political parties, contractual arrangements for staff, individual champions, progress in mainstreaming). On this basis, conclusions are drawn regarding how to foster sustainable and transformative adaptation through increased stakeholder involvement. The results and conclusions are crucial to advance theory on adaptation co-production, providing a basis for further analyses, research and action. They inform how existing theory, policies and/or guidelines for strategic adaptation planning need to be revisited to support change across current risk governance.  相似文献   
167.
In this study, an interactive two-stage stochastic fuzzy programming (ITSFP) approach has been developed through incorporating an interactive fuzzy resolution (IFR) method within an inexact two-stage stochastic programming (ITSP) framework. ITSFP can not only tackle dual uncertainties presented as fuzzy boundary intervals that exist in the objective function and the left- and right-hand sides of constraints, but also permit in-depth analyses of various policy scenarios that are associated with different levels of economic penalties when the promised policy targets are violated. A management problem in terms of water resources allocation has been studied to illustrate applicability of the proposed approach. The results indicate that a set of solutions under different feasibility degrees has been generated for planning the water resources allocation. They can help the decision makers (DMs) to conduct in-depth analyses of tradeoffs between economic efficiency and constraint-violation risk, as well as enable them to identify, in an interactive way, a desired compromise between satisfaction degree of the goal and feasibility of the constraints (i.e., risk of constraint violation).  相似文献   
168.
We derive conditions under which raising costs through a regulatory constraint or a fully expropriated tax can increase the profits arising from a common-pool resource. The basic model assumes a fixed number of identical agents with linear costs selling in a single period at an exogenous price. A necessary and sufficient condition for a cost increase to be profitable is that aggregate output from the resource be locally convex in aggregate effort. We also show that cost increases can be profitable even if price is endogenous, agents are heterogeneous, entry is costless, or agents are playing a Markov-perfect equilibrium of a dynamic game. We also discuss more general welfare implications of the result along with its relation to existing results for a Cournot oligopoly.  相似文献   
169.
A rapid and sustained transition to new energy systems for Australia was explored using the OzECCO model implemented in a systems dynamics simulation package. OzECCO simulates the close relationship between energy use and economic productivity at a sectoral level to explore scenarios of economic and biophysical function based on a calibration period of 1981-2005 and a scenario period 2006-2051. The core scenarios showed that a fully renewable (the renewables transition) or an advanced fossil and nuclear transition (the conventional wisdom transition), can reduce accumulated CO2 emissions from the Australian economy for the period 2006-2051 by 50%. Adding a low growth economy where GDP averages less than 1% annually extends this to a 60% reduction. Extensive reforestation of more than 50 million hectares extends the total reduction to 70% over the 45 year period and provides at 2051 a per capita emissions level of one to two tonnes which will be necessary if developed and developing countries are to converge on equal atmospheric impacts with reasonable lifestyle opportunities. Central to both the renewables and conventional-wisdom scenarios are substantial reductions in the physical dimensions of personal consumption, and the transfer of these avoided consumption opportunities to an intergenerational sovereign wealth fund. This fund, held outside day-to-day domestic activities, can buffer Australian society and future generations against shocks, financial or physical, that might lie waiting and unanticipated in our future. This study did not explore phasing out Australia's extensive coal and natural gas exports although their impact on global atmospheric concentrations is significant. Domestic combustion and exported fuels will add 82 billion tonnes of CO2 to the atmosphere in the scenario period 2006-2051, equivalent to a 20 ppm rise in atmospheric concentrations. The low-growth renewables transition with unconstrained exports reduces this rise to 15 ppm. The continued expansion of fuel exports thus expands atmospheric risk in physical terms but also entrains policy and strategic risks should carbon-based industries become pariahs in international commerce and political relations.  相似文献   
170.
Policy and human livelihoods modelling increasingly demands integrated research which requires ecological expertise. However, contributions from ecologists are often based on sparse data. Rather than discounting such data, in this paper we demonstrate how ecological modelling can effectively contribute to the development of policy recommendations in spite of data constraints. In a petrol subsidy analysis in East Kalimantan, Indonesia, we accounted for ecological data uncertainty by (a) assuming large parameter value ranges and (b) conducting a robustness test for policy recommendations. In addition to data scarcity, counter-intuitive results emerged emphasising the need for model validation. These counter-intuitive results indicated that decreasing petrol prices led to increased poverty. This informed a policy recommendation to prevent the reduction of petrol prices below IDR 5500 per litre. Using two key livelihood resources (fish and honey), we found that while a traditional sensitivity analysis suggested highly robust results, a robustness test indicated that policy recommendations would change if the incorrectness of parameter values approached 50%. The results show that ecological modelling can contribute effectively in spite of sparse data to guide policy, as well as identifying future research priorities.  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