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   800篇
  免费   23篇
  国内免费   39篇
安全科学   46篇
废物处理   10篇
环保管理   272篇
综合类   167篇
基础理论   128篇
环境理论   2篇
污染及防治   57篇
评价与监测   56篇
社会与环境   111篇
灾害及防治   13篇
  2023年   4篇
  2022年   18篇
  2021年   16篇
  2020年   21篇
  2019年   22篇
  2018年   19篇
  2017年   18篇
  2016年   29篇
  2015年   23篇
  2014年   29篇
  2013年   91篇
  2012年   27篇
  2011年   70篇
  2010年   25篇
  2009年   70篇
  2008年   64篇
  2007年   64篇
  2006年   35篇
  2005年   29篇
  2004年   26篇
  2003年   27篇
  2002年   19篇
  2001年   28篇
  2000年   28篇
  1999年   17篇
  1998年   4篇
  1997年   7篇
  1996年   3篇
  1995年   4篇
  1994年   5篇
  1993年   4篇
  1992年   1篇
  1991年   2篇
  1990年   4篇
  1989年   1篇
  1988年   2篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1982年   1篇
  1972年   1篇
排序方式: 共有862条查询结果,搜索用时 531 毫秒
521.
基于压力论的城市生态环境质量定量评价模型及应用   总被引:1,自引:0,他引:1  
本文从压力源-压力流-压力汇的角度构建城市生态环境质量评价指标体系,并对上海闵行区的生态环境质量进行了评价,结果表明闵行区城市生态环境质量的压力源虽然逐年来有所增加,但是其城市生态环境质量的支持力则呈现逐年增大的趋势,故闵行区城市生态环境质量总体向较为理想的趋势在发展。  相似文献   
522.
初步建立了面向生命周期评价(LCA)的适合我国土地利用生态影响评价的指标、特征化因子和影响大小计量模型.评价指标包括土地利用时间、面积、净初级生产力、土壤有机质含量和地形坡度.分别研究确定了基于NPP、土壤有机质含量和地形坡度的特征化因子及其当量系数.提出了基于顶级群落理论的土地利用生态影响评价计量模型.案例应用表明,提出的方法可为我国开展土地利用的LCA提供初步的技术框架和相关参数.  相似文献   
523.
This paper discusses the conceptual basis for linking development policies and climate change adaptation and mitigation and suggests an analytical approach that can be applied to studies in developing countries. The approach is centred on a broad set of policy evaluation criteria that merge traditional economic and sectoral goals and broader social issues related to health and income distribution. The approach is inspired by institutional economics and development paradigms that emphasise human wellbeing, resource access, empowerment, and the arrived freedoms. It is outlined how indicators of wellbeing can be used to assess policies that integrate development and climate change policy objectives, and this approach is discussed in comparison with other work that rather have been inspired by sustainable development aspects of manmade, natural, and social capital. The experiences and results from case studies of development and climate that have done a first attempt to use human wellbeing indicators are reported and discussed. The studies include work from India, China, South Africa, Brazil, Bangladesh, and Senegal. A number of policy examples in the energy-, food-, and water sectors in these studies have shown up to demonstrate numerous linkages between development policies and climate change. Various analytical tools have been used in the studies including quantitative and qualitative scenario work as well as detailed micro-based analysis. The methodological conclusion that can be drawn from these studies, is that it is possible to apply wellbeing indicators to the more detailed policy assessment, but a link to more general national and regional scenario work is not yet established.  相似文献   
524.
会仙岩溶湿地丰平枯水期地表水污染及灌溉适用性评价   总被引:1,自引:0,他引:1  
以我国典型的亚热带低海拔岩溶湿地为研究区,对该区丰水期、平水期和枯水期共采集的27组地表水样品进行12种常规离子和10种金属元素检测,在分析地表水主要离子化学特征基础上,分别运用内梅罗污染指数法以及钠吸附比法(SAR)、钠含量法(SC)、渗透指数法(PI)和残余碳酸钠法(RSC)这4种评价体系对不同时期地表水进行污染评价和灌溉适用性评价.结果表明,研究区内地表水主要为弱碱性水,Ca2+和HCO3-为优势离子.常规指标中仅NH4+超过生活饮用水卫生标准限值,超标率为25.93%,金属元素中超标组分为Al(11.11%)、Mn(44.44%)和Hg(37.04%).常规指标浓度受时空尺度影响程度整体低于金属元素,两者均具有丰水期 > 平水期 > 枯水期的时期分布特征.据污染评价结果,区内地表水总体水质尚可,内梅罗综合污染指数介于0.75~2.69,主要污染指标为NH4+、Mn、Al和Hg,部分样点存在季节性污染,污染级别为轻度~中度,丰水期污染程度最高,污染点多分布于湿地核心区.综合农田灌溉水质标准和地表水环境质量标准限值以及SAR、SC、PI和RSC灌溉适用性评价结果,会仙岩溶湿地地表水总体适合灌溉,枯水期灌溉适用性优于丰水期和平水期,平水期PH1(Hg浓度1.91 μg·L-1)和丰水期FH8(NH4+浓度13.70 mg·L-1)地表水已不适用于农业灌溉.  相似文献   
525.
建立健全生态产品价值实现机制是践行习近平生态文明思想的重要举措。随着"绿水青山就是金山银山"理念转化探索实践的不断深入,围绕生态产品供给和价值实现形成的新产业、新业态、新模式不断涌现,生态产品产业有望成为经济高质量发展的新动力和生态文明建设的新模式。本文基于生态产品价值实现的理论和实践,首次提出了生态产品第四产业的概念及内涵特征,初步分析了生态产品第四产业的形成机制和构成要素。结合不同市场属性生态产品的价值实现路径,初步梳理了生态产品第四产业形态,界定了其产业范围,设计了衡量生态产品第四产业核算与发展指标体系,并从供给、消费、交易和利益分配等维度提出了促进生态产品第四产业的政策保障。研究认为,我国生态产品第四产业发展具有很好的基础和前景,应以习近平生态文明思想为指导,加快完善生态产品价值实现机制,让生态产品第四产业发展成为我国新时期的朝阳绿色产业。  相似文献   
526.
Abstract: Wastewater impact on drinking water sources was assessed using several approaches, including analysis of three pharmaceuticals and personal care products (PPCPs) – primidone, carbamazepine, and caffeine – as indicators, and determination of precursor concentrations for the disinfection byproduct N‐nitrosodimethylamine (NDMA) using formation potential (FP) tests. Samples were collected in 2006 and 2007 in rivers impacted by wastewater treatment plant (WWTP) discharges, at drinking water treatment plant (DWTP) intakes upstream or downstream from these discharges, and from two WWTP effluents in two watersheds. The levels [10th percentile ? maximum (median)] of primidone, carbamazepine, caffeine, and NDMAFP were 2‐95 (7) ng/l, 2‐207 (18) ng/l, 7‐687 (78) ng/l, and 12‐321 (35) ng/l, respectively. The highest concentrations of primidone, carbamazepine, and NDMA precursors were from one of the WWTP effluents, whereas the highest concentration of caffeine was detected in a river heavily impacted by treated wastewater discharges. The lowest concentrations of the three PPCPs were from a DWTP influent upstream of a metropolitan urban area with minimum wastewater impact. Temporal variations in PPCP and NDMAFP concentrations and streamflows in two selected watersheds were also observed. Furthermore, correlation analysis between caffeine or carbamazepine and primidone was evaluated. The results show that measurement of the two pharmaceuticals and NDMAFP tests can be used to evaluate wastewater impact in different watersheds, whereas caffeine results were more variable.  相似文献   
527.
Development of Environmental Indicator Systems: Experiences from Germany   总被引:44,自引:0,他引:44  
ABSTACT / Environmental indicator systems aim to improve both the information and communication on the state of the environment and the environmental policy making. They have to fulfill scientific, functional and pragmatic requirements, e.g., consideration of ecological context, transparency and reproducibility, comprehensibility, policy relevance, international comparability, and justifiable expenditure. This paper analyzes the experiences made with the development of the German environmental indicator system and draws general conclusions toward further improvements. For Germany, an indicator system has been developed that uses the pressure-state-response approach proposed by the OECD, together with a classification in 14 environmental themes. According to the general requirements, the main criteria used for selecting the indicators are the ecological significance of the indicator, its quantifiability and data availability, and its comprehensibility and policy relevance. Altogether, about 140 indicators are selected. This high number stresses the need for further high-level aggregation, e.g., using methods developed for the valuation process in LCA. Further improvement is also needed, especially for the development of response indicators and in the area of data systematization.  相似文献   
528.
河岸带地下水理化指标变化及与洪水的响应关系研究   总被引:1,自引:4,他引:1  
河岸带地下水和河水存在复杂的交互作用,地下水和地表水存在明显的补排关系,洪水事件是影响河岸带地下水水质波动的重要水文过程.以黄河湿地国家级自然保护区孟津湿地为对象,通过河岸带地下理化指标(特别是小浪底水库调水调沙期间)野外定位观测,深入分析了河岸带地下水水质与洪水的响应关系.结果表明,受河流与荷塘蓄水的影响,地下水温度...  相似文献   
529.
城市生态系统健康评价新模型及应用——以天津市为例   总被引:3,自引:1,他引:3  
从城市生态系统的活力、组织结构、恢复力、生态系统服务功能及人群健康5个方面建立了城市生态系统健康评价的指标体系,并针对目前现有的城市生态系统健康评价模型的不足,以最大流原理为基础,以自组织特征映射神经网络(SOM)为算法实现手段,从复杂系统结构演化的角度提出了一个新的城市生态系统健康评价模型.进而使用该模型对2001-2009年天津市生态系统健康进行评价.结果表明,天津市2001-2007年城市生态系统处于亚健康状况,2008、2009年处于较健康的状况,并得出天津市生态系统健康状况处于逐年增长的趋势的判定.由于该模型从一定程度上体现了城市生态系统健康的演化动力学机理和城市生态系统时空演变特性,因此,不仅在评价上有较大的优越性,在城市生态系统健康发展变化状态的预测上也具有潜力.  相似文献   
530.
Some of the modern criteria for assessing ecosystem health are compared with current understanding of ecosystem function in rivers. Owing to the predominance of catchment imports over autochthonous primary production, most rivers are naturally heterotrophic. This does not make them unhealthy but the pristine condition is that much harder to determine. The case is put for an index of ecosystem health and sustainability that takes into account the system's capacity for processing its resources, the species richness and its interdependence and its resilience to external forcing. Although these are not easily quantified, the qualitative indicators of healthy ecosystem function are easily checked. The sensitivity of organisms in suspension to fluvial flow may seem to counter the suitability of plankton as a reliable state indicator of river health. On the other hand, the rules governing the assembly of planktic communities in rivers are often strict and quantifiable: this makes them attractive candidates to act as indicators of the ecological condition of rivers.  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