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91.
随着技术水平提升及生活水平的提高,家电产品的更新换代也越来越快,废旧家电的末端治理问题亟待优化。以北京市为例,运用等维灰数递补动态预测方法研究4类主要家电的销量,发现自2010年起,北京市的家电销售量迅猛增长,并在此基础上预测了2013--2016年废旧家电的产生量,并就规范当前回收体系提出可行一性建议。  相似文献   
92.
Mapping Human Dimensions of Climate Change Research in the Canadian Arctic   总被引:2,自引:0,他引:2  
This study maps current understanding and research trends on the human dimensions of climate change (HDCC) in the eastern and central Canadian Arctic. Developing a systematic literature review methodology, 117 peer reviewed articles are identified and examined using quantitative and qualitative methods. The research highlights the rapid expansion of HDCC studies over the last decade. Early scholarship was dominated by work documenting Inuit observations of climate change, with research employing vulnerability concepts and terminology now common. Adaptation studies which seek to identify and evaluate opportunities to reduce vulnerability to climate change and take advantage of new opportunities remain in their infancy. Over the last 5 years there has been an increase social science-led research, with many studies employing key principles of community-based research. We currently have baseline understanding of climate change impacts, adaptation, and vulnerability in the region, but key gaps are evident. Future research needs to target significant geographic disparities in understanding, consider risks and opportunities posed by climate change outside of the subsistence hunting sector, complement case study research with regional analyses, and focus on identifying and characterizing sustainable and feasible adaptation interventions.  相似文献   
93.
厌氧折流板反应器(ABR)中成熟颗粒污泥的分形分析   总被引:5,自引:0,他引:5  
研究了ABR反应器启动成功后成熟颗粒污泥的物理性质和不同拓扑空间下的分形维数.结果表明,在反应器启动成功后,各格室中形成了平均粒径为1.70~2.70 mm、边界较为清晰的黑色颗粒污泥.它们的SVI值为25~35 mL·g-1,有效密度主要集中在1.02g·mL-1以下,自由沉降速率主要集中在14.40~86.40m·h-1之间.在它们的等速自由沉降的过程中,第2格室到第5格室中颗粒污泥水平方向的投影平均直径与垂直投影方向上平均直径的比值接近0.73,而第1格室的这一比值却为0.83.依据沉降速率-当量圆直径的双对数图计算出的各格室中颗粒污泥的质量分形维数Df处于2.097~2.801之间,大小顺序为第5格>第3格>第2格≥第1格>第4格,表明第5格室中形成的颗粒污泥较为密实,而第4格室的密实程度最小,但密实的颗粒污泥并不一定意味着较高的平均沉降速率.此外,依据投影法计算出的ABR各格室中颗粒污泥在低维拓扑空间下的几种分形维数之间的关系与其理论公式之间的关系相符,其中二维拓扑空间的分形维数为1.69~1.84(投影面积-长轴),大小顺序为第3格室>第1格室>第5格室>第4格室>第2格室,这些D2不等于2,即不符合Meakin的结论.一维拓扑空间下的分形维数在0.99~1.03之间,各格室之间差异不大,表明颗粒污泥的边界不规则程度小.  相似文献   
94.
We reviewed recent work concerning the impact of geopolitics on wildlife conservation (and vice versa) and identified future priorities in conservation geopolitics research. Geopolitics is understood as both an analytical focus on geopolitical practices (especially concerning the behavior) of countries with respect to territory and national security and a set of theories developed to explain and predict those behaviors. We developed a typology of core geopolitical practices of relevance to conservation: territorial practices of colonization and the management of migrations and borders, and security practices relating to military, economic, and environmental security. We identified research that considers how these practices affect conservation situations and outcomes, noting the recent emergence of conceptual developments such as “environmental geopolitics” and “geopolitical ecology” that draw on multiple fields within the social sciences to theorize the links between geopolitics and environmental management. We defined a "geopolitical perspective" as a focus on geopolitical practices combined with an explicit engagement with geopolitical theory and identified conservation situations where this perspective could contribute to analytical clarity. We suggest the most pressing questions in conservation research to which the geopolitical perspective might contribute are how political and economic differences between countries affect biodiversity outcomes, how geopolitical practices to address those differences facilitate or frustrate conservation efforts, how national borders and human and wildlife movements can be better managed for the benefit of both, and how the most effective conservation strategies can be best selected to suit existing (and future) geopolitical realities.  相似文献   
95.
吴超 《安全》2019,40(8):32-37,42
由于安全问题的复杂性和多样性,安全理论一般都很难被广大安全工作者高度认同。因此,亟需研究厘清安全的维度、给出安全研究的预设、梳理安全研究的途径和开拓新的安全理论。本文运用理论研究、科学分类和逻辑思辨等方法对上述几个方面的问题开展研究,首先从安全边界、安全主体、安全物资、安全环境、安全知识、安全管理、安全信息7个方面梳理了安全的维度,给出了几条安全研究的预设;其次,梳理了从事故预防、风险管理和本源安全出发的安全研究3条途径,并比较了它们的优缺点等;最后综述了近年出现的3种安全新思想。研究结果对认识安全研究的复杂性、合理选择安全研究路径、寻找未来安全工作新方向新领域等具有重要的理论和实际意义。  相似文献   
96.
Investigation of the social framing of human–shark interactions may provide useful strategies for integrating social, biological, and ecological knowledge into national and international policy discussions about shark conservation. One way to investigate social opinion and forces related to sharks and their conservation is through the media's coverage of sharks. We conducted a content analysis of 300 shark‐related articles published in 20 major Australian and U.S. newspapers from 2000 to 2010. Shark attacks were the emphasis of over half the articles analyzed, and shark conservation was the primary topic of 11% of articles. Significantly more Australian articles than U.S. articles treated shark attacks (χ2 = 3.862; Australian 58% vs. U.S. 47%) and shark conservation issues (χ2 = 6.856; Australian 15% vs. U.S. 11%) as the primary article topic and used politicians as the primary risk messenger (i.e., primary person or authority sourced in the article) (χ2 = 7.493; Australian 8% vs. U.S. 1%). However, significantly more U.S. articles than Australian articles discussed sharks as entertainment (e.g., subjects in movies, books, and television; χ2 = 15.130; U.S. 6% vs. Australian 1%) and used scientists as the primary risk messenger (χ2 = 5.333; U.S. 25% vs. Australian 15%). Despite evidence that many shark species are at risk of extinction, we found that most media coverage emphasized the risks sharks pose to people. To the extent that media reflects social opinion, our results highlight problems for shark conservation. We suggest that conservation professionals purposefully and frequently engage with the media to highlight the rarity of shark attacks, discuss preventative measures water users can take to reduce their vulnerability to shark encounters, and discuss conservation issues related to local and threatened species of sharks. When integrated with biological and ecological data, social‐science data may help generate a more comprehensive perspective and inform conservation practice. Descripción de Tiburones y su Conservación por Medios Informativos Australianos y Norteamericanos  相似文献   
97.
Abstract

Prevention of marine pollution, particularly in semi-enclosed seas, embayments and areas with limited exchange of water, requires a well conceived and harmonized legal system, specified standards, a monitoring programme, and effective control and enforcement capabilities. This comprehensive approach is often called a strategy. Three generations of strategies have been devised and applied historically in Europe and North America, each a step further in integrating environmental protection, technical advancement and economic capabilities. the overpowering socio-economic problems of transition from a centrally planned to a market economy, a task facing a dozen central and eastern European coastal states, compound the problem of application of an integrated approach.

No management strategy can achieve its set goals unless based on scientific evidence. the data base has to offer information on two basic questions, one specific and one of a general nature.

The specific question is: Has the area under consideration some features, an activity, or one or more living species, which must be protected at any cost? the answer to this question will invoke the precautionary principle into strategic considerations, and leads to the general question: What is the carrying (= assimilative or environmental) capacity for each activity and for the discharge of each contaminant into the impacted area? Answers to these questions lead to the choice of the strategy for environmental management.  相似文献   
98.
研究了厌氧折流板反应器(ABR)中成熟颗粒污泥和某污水处理厂回流、厌氧、曝气、消化4个单元中絮状污泥的一维、二维分形维数(D1、D2、D′2)及平均粒径在不同统计样本数下的变化规律。结果表明,当统计样本数达到200以上时,ABR中成熟颗粒污泥的D1、D2、D′2值趋于稳定;当样本数达到300以上时,某污水处理厂4个单元中絮状污泥的D1、D2、D′2值也分别趋于稳定。此外,1#ABR中的颗粒污泥在统计样本数达到350以上时其中位直径趋于稳定,而2#ABR和某污水处理厂4个处理单元中的污泥,在试验样本数下并未达到稳定。基于研究的结果和相关文献的结论,研究认为,如果需要得到稳定的平均粒径结果,可能需要大量的统计样本数,该样本数至少要大于600。  相似文献   
99.
Channel dimensions (width and depth) at varying flows influence a host of instream ecological processes, as well as habitat and biotic features; they are a major consideration in stream habitat restoration and instream flow assessments. Models of widths and depths are often used to assess climate change vulnerability, develop endangered species recovery plans, and model water quality. However, development and application of such models require specific skillsets and resources. To facilitate acquisition of such estimates, we created a dataset of modeled channel dimensions for perennial stream segments across the conterminous United States. We used random forest models to predict wetted width, thalweg depth, bankfull width, and bankfull depth from several thousand field measurements of the National Rivers and Streams Assessment. Observed channel widths varied from <5 to >2000 m and depths varied from <2 to >125 m. Metrics of watershed area, runoff, slope, land use, and more were used as model predictors. The models had high pseudo R2 values (0.70–0.91) and median absolute errors within ±6% to ±21% of the interquartile range of measured values across 10 stream orders. Predicted channel dimensions can be joined to 1.1 million stream segments of the 1:100 K resolution National Hydrography Dataset Plus (version 2.1). These predictions, combined with a rapidly growing body of nationally available data, will further enhance our ability to study and protect aquatic resources.  相似文献   
100.
Ten Key Questions About the Management of Water in the Yellow River Basin   总被引:3,自引:0,他引:3  
Water is scarce in many regions of the world, clean water is difficult to find in most developing countries, there are conflicts between irrigation needs and urban demands, and there is wide debate over appropriate means of resolving these problems. Similarly, in China, there is limited understanding of the ways in which people, groups, and institutions contribute to, are affected by, and respond to changes in water quantity and quality. We use the example of the Yellow River basin to argue that these social, managerial, and policy dimensions of the present water problems are significant and overshadow the physical ones. Despite this, they receive relatively little attention in the research agenda, particularly of the lead agencies in the management of the Yellow River basin. To this end, we ask ten research questions needed to address the policy needs of water management in the basin, split into two groups of five. The first five relate to the importance of water in this basin and the changes that have affected water problems and will continue to do so. The second five questions represent an attempt to explore possible solutions to these problems.  相似文献   
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