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   422篇
  免费   51篇
  国内免费   62篇
安全科学   40篇
环保管理   127篇
综合类   174篇
基础理论   74篇
污染及防治   27篇
评价与监测   10篇
社会与环境   44篇
灾害及防治   39篇
  2024年   2篇
  2023年   12篇
  2022年   20篇
  2021年   15篇
  2020年   19篇
  2019年   18篇
  2018年   12篇
  2017年   26篇
  2016年   21篇
  2015年   28篇
  2014年   23篇
  2013年   35篇
  2012年   33篇
  2011年   25篇
  2010年   21篇
  2009年   16篇
  2008年   17篇
  2007年   37篇
  2006年   16篇
  2005年   10篇
  2004年   13篇
  2003年   9篇
  2002年   6篇
  2001年   8篇
  2000年   7篇
  1999年   7篇
  1998年   6篇
  1997年   3篇
  1996年   11篇
  1995年   5篇
  1994年   11篇
  1993年   3篇
  1992年   4篇
  1991年   2篇
  1990年   4篇
  1989年   6篇
  1988年   2篇
  1986年   3篇
  1984年   2篇
  1983年   2篇
  1982年   2篇
  1980年   1篇
  1979年   2篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1973年   2篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
排序方式: 共有535条查询结果,搜索用时 226 毫秒
431.
本文讨论了有关:1)痕量元素地球化学背景值;2)痕量元素地球化学表征;及3)我国某些地区若干痕量元素的背景值。  相似文献   
432.
ABSTRACT: Scarcity combined with differences in values, beliefs, and attitudes can lead to behavior differences and conflicts over water. This paper develops an index for measuring potential conflict using survey information about water attitudes and beliefs of individuals in three groups in a Florida case study. The index helps in assessing the current capability of the institution to reduce conflict. The results suggest that the current institution is effective, but changes may help to streamline the consumptive-use permitting process, to improve educational programs, and to seek improved institutional arrangements to reduce future conflict over economic uses of water.  相似文献   
433.
The fast-degrading land resources of Swaziland requires a multi-faceted approach to their management. One resource of utmost importance to all Swazis is grass. Grass research over the years had focused on pasture grass, while other uses have been neglected. The omission is a serious one and could be attributed to the neglect of indigenous grass knowledge and people's socio-economic values of grasses. Grass as a major resource is used for cattle feed, ecological control measures, medicinal plants and crafts. Within the study area, 46 grass species were identified and described by the local people. The neglect of the people's knowledge and utilitarian values of grass is a waste of resources. Thus, for grass research to be relevant to the people and national development objectives, research scientists should rethink their approach; they need to recognize and incorporate the indigenous knowledge about other uses of grasses.  相似文献   
434.
ABSTRACT: This paper uses the fundamental values of decision makers to guide a long-term wastewater planning process at Seattle Metro, a major utility district. Multiattribute value assessment is used to elicit the objectives of several elected officials and other key decision makers. The results are structured into a fundamental objectives hierarchy and a means-ends objectives network. A set of measures to indicate the performance of planning alternatives in terms of the fundamental objectives is developed. Preliminary value tradeoffs between objectives are elicited from several elected officials. The results of these steps are useful for many aspects of long-term planning: facilitating communication about values and priorities; designing attractive alternatives that are more likely to serve stakeholder interests; identifying information needed to evaluate alternatives; clarifying the relative importance of information about different impacts; providing a basis for quantitative evaluation of the alternatives with multiple objective analysis; and focusing attention on key tradeoffs that will affect the choice of alternatives.  相似文献   
435.
ABSTRACT: Records of extreme precipitation were investigated using the Discrete Autoregressive Moving Average (DABMA) process, which can explain long persistences of wet and dry spells that exist in daily precipitation data. The results show that the daily precipitation with strong autocorrelation is inclined to be better fit by a Discrete Autoregressive (DAB) model. On the other hand, those data with weak autocorrelations tend to be best fit by a Discrete Moving Average (DMA) model. It can also be concluded that based on the records from extremely wet and dry regions there is no geographic preference regarding the selection of the best model.  相似文献   
436.
社会环境道德价值观发展阶段与可持续发展   总被引:12,自引:0,他引:12  
社会环境道德价值观是人们对人与自然环境道德关系的一种普遍的社会意识,它作为环境意识的核心内容,决定着人们的环境行为取向。当前我国社会环境道德价值观发展正处于从传统人类中心主义向现代人类中心主义的转变阶段。为实现我国可持续发展目标,社会环境道德价值观尚须由现代人类中心主义阶段向生存系统协调论阶段迈进。  相似文献   
437.
Conventional measures of economic output, national income and wealth highly underestimate the value and contribution of natural resources to economic welfare. This paper makes estimates of the asset values and flow benefits of non-traded goods and services from forests and woodland resources in South Africa. Four benefit categories were included, namely direct consumptive use values (timber and non-timber products), non-consumptive use values (recreation for example), indirect use values (environmental services such as carbon sequestration, watershed protection, etc.), and non-use values (based on contingent valuation by tourists). Asset values were calculated knowing the change in physical stocks and the relevant prices. In South Africa, the increase in assets was equivalent to 1.1% of gross domestic product (GDP) (forests were improving, but fynbos deteriorating), and the flow benefits were equivalent to 0.8% of GDP. These are large magnitudes.  相似文献   
438.
Though still relatively new, the development of marine spatial planning has been based on the on the premise that as a rational planning process, it can be applied following universal principles and steps informed by land-based inspired theoretical underpinnings. However, within this process, differences between marine and terrestrial environments are being overlooked, potentially affecting the way in which the marine environment is understood and valued, and the development of a culture of practice for, and specific to, marine spatial planning. By framing planning as a cultural construct, this paper aims to explore the extent to which land-based rationales are affecting the development of a marine spatial planning culture of practice, with its own ethos and shared values. A culturalised planning model adapted from [Knieling, J. and Othengrafen, F. (2015). Planning culture—a concept to explain the evolution of planning policies and processes in Europe? European Planning Studies, 23(11), 2133–2147] is used as a framework. Whilst acknowledging the importance of the contributions from land-based planning and the ecological sciences, the findings suggest that those unconscious beliefs and perceptions affecting society’s understanding of the marine environment should contribute to informing shared values for marine spatial planning practice.  相似文献   
439.
Based on the reasoning that contextual variations are important for understanding differences in forest cognitions, this study examined forest values and management attitudes in the general public in Germany (n = 1135) and Sweden (n = 1311) by means of a questionnaire. Results indicated that the public in both countries emphasised similar forest values, and the overall pattern was comparable for different types of forest, although certain differences based on forest type and country were evident. For example, the German public was more ecologically oriented, whereas the Swedish public was more production oriented in its forest values and management attitudes. Furthermore, ecological and various anthropocentric forest values were perceived to be quite compatible, with the Swedish respondents perceiving this to a greater extent than the German. The overall cognitive structure of forest values and management attitudes was similar in both countries, although differences were revealed, particularly regarding attitudes.  相似文献   
440.
Australia's Murray–Darling basin (MDB) water plan is an ambitious attempt to balance ecological, social and economic benefits, where a key aspect of the reform process has been recovery of water for environmental use. This paper focuses on a set of initiatives established by a local non-governmental organisation and an Indigenous community designed to engage with local values and priorities and incorporate them into this complex river basin governance system. Contrary to expectations that local and basin-scale interests and outcomes will diverge, the case studies reveal the ability for local groups to collaboratively manage both land and water resources to achieve locally important outcomes, and contribute to basin-scale outcomes. The analysis also highlights a progressive style of community-based environmental management for water management that utilises multiple institutional arrangements and planning pathways to protect the values that are important to local communities, and to nest those values within the broader effort to sustainably manage the basin's water resources.  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