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   240篇
  免费   2篇
  国内免费   1篇
安全科学   2篇
废物处理   13篇
环保管理   34篇
综合类   31篇
基础理论   52篇
污染及防治   70篇
评价与监测   27篇
社会与环境   10篇
灾害及防治   4篇
  2023年   5篇
  2022年   9篇
  2021年   11篇
  2020年   3篇
  2019年   9篇
  2018年   12篇
  2017年   10篇
  2016年   17篇
  2015年   9篇
  2014年   10篇
  2013年   23篇
  2012年   17篇
  2011年   13篇
  2010年   11篇
  2009年   10篇
  2008年   13篇
  2007年   19篇
  2006年   13篇
  2005年   4篇
  2004年   6篇
  2003年   2篇
  2002年   4篇
  2001年   3篇
  2000年   4篇
  1999年   1篇
  1995年   1篇
  1990年   1篇
  1981年   1篇
  1958年   1篇
  1956年   1篇
排序方式: 共有243条查询结果,搜索用时 31 毫秒
181.
Regional Environmental Change - Ecosystem services (ES) management has to cope with a high degree of uncertainty related to changes in socio-economic and climatic conditions as well as in societal...  相似文献   
182.
Mountain landscapes are undergoing rapid land-use changes. Settlement expansion, the intensification of agricultural land-use practices, and farmland abandonment result in a decline of natural and semi-natural habitats and the related ecosystem services (ES). In this context, spatial planning has emerged as a key instrument for the management of ES provision. To better understand trade-offs and interactions between settlement growth and ES provision in a spatially explicit manner, we present a new modeling framework coupling an agent-based, agro-economic optimization model and a cellular-automata-based settlement growth model. The framework is applied in an inner alpine valley in the Valais, Switzerland, which experienced rapid settlement growth in recent years. Results demonstrate how the model framework allows support of local planning processes. Particularly cooperation among municipalities and an explicit consideration of ES can inform spatially explicit ES trade-off decisions under increasing demand for land. We conclude that better informed spatial planning processes support ES provision.  相似文献   
183.
Effects of triclosan on zebrafish early-life stages and adults   总被引:1,自引:0,他引:1  

Background, aim and scope  

The biocide triclosan (TCS) is commonly used in personal care, acrylic, plastic, and textiles products. TCS has been detected in surface water in several countries, and its ecological impact is largely unknown. In this work, the toxicity of TCS in zebrafish (Danio rerio), embryos and adults was studied. Several lethal and sub-lethal endpoints were analysed in organisms exposed to TCS such as mortality, embryo development and behaviour, hatching, micronuclei and biochemical markers (cholinesterase (ChE), glutathione S-transferase (GST) and lactate dehydrogenase (LDH)).  相似文献   
184.
The ozone in Rio de Janeiro has been in violation of national air quality standards. Among all of the monitoring stations, the Bangu neighbourhood has the most violations of the national standard of 160 μg m?3 for the years 2012 and 2013. This study evaluated the reactivity of the carbonyls and aromatics in the tropospheric ozone formation processes. The samples were collected between July and October of 2013. Carbonyls were sampled using SiO2 cartridges coated with C18 and impregnated with 2,4-dinitrophenylhydrazine and were analysed by HPLC. Activated carbon cartridges and GC/MS were used to measure the concentration of monoaromatic hydrocarbons. An air quality monitoring station provided the concentrations of the criteria pollutants and the meteorological parameters. Cluster analysis and a Pearson correlation matrix were used to determine the formation of groups and the correlation of the variables. The evaluation of the volatile organic compounds (VOC) reaction with OH radicals and the MIR scale was used to extrapolate the reactivity of VOCs to the ozone formation. The average concentrations obtained were 19.7 and 51.9 μg m?3 for formaldehyde and acetaldehyde, respectively. The mean concentrations obtained for aromatics were 1.5, 6.7, 1.5, 2.6 and 1.6 μg m?3 for benzene, toluene, ethyl benzene, m+p-xylene and o-xylene, respectively. The cluster analysis indicated the presence of three similar groups, with one formed by gaseous criteria pollutants, another formed by the meteorological parameters, ozone and fine particles, and the last group formed by the aromatics. For the two reactivity scales evaluated, acetaldehyde and toluene were the main ozone precursors.  相似文献   
185.
186.
Ozone (O3) is a toxic secondary pollutant able to cause an intense oxidative stress that induces visual symptoms on sensitive plant species. Controlled fumigation experiment was conducted with the aim to verify the O3 sensibility of three tropical species: Piptadenia gonoachanta (Mart.) Macbr. (Fabaceae), Astronium graveolens Jacq. (Anacardiaceae), and Croton floribundus Spreng. (Euphorbiaceae). The microscopical features involved in the oxidative stress were recognized based on specific histochemical analysis. The three species showed visual symptoms, characterized as necrosis and stippling between the veins, mostly visible on the adaxial leaf surface. All the studied species presented hypersensitive-like response (HR-like), and peroxide hydrogen accumulation (H2O2) followed by cell death and proanthocyanidin oxidation in P. gonoachanta and A. graveolens. In P. gonoachanta, a decrease in chlorophyll autofluorescence occurred on symptomatic tissues, and in A. graveolens and C. floribundus, a polyphenol compound accumulation occurred. The responses of Brazilian native species were similar to those described for sensitive species from temperate climate, and microscopical markers may be useful for the detection of ozone symptoms in future studies in the field.  相似文献   
187.
Although widely used in air quality regulatory frameworks, the term “volatile organic compound” (VOC) is poorly defined. Numerous standardized tests are currently used in regulations to determine VOC content (and thus volatility), but in many cases the tests do not agree with each other, nor do they always accurately represent actual evaporation rates under ambient conditions. The parameters (time, temperature, reference material, column polarity, etc.) used in the definitions and the associated test methods were created without a significant evaluation of volatilization characteristics in real world settings. Not only do these differences lead to varying VOC content results, but occasionally they conflict with one another. An ambient evaporation study of selected compounds and a few formulated products was conducted and the results were compared to several current VOC test methodologies: SCAQMD Method 313 (M313), ASTM Standard Test Method E 1868-10 (E1868), and U.S. EPA Reference Method 24 (M24). The ambient evaporation study showed a definite distinction between nonvolatile, semivolatile, and volatile compounds. Some low vapor pressure (LVP) solvents, currently considered exempt as VOCs by some methods, volatilize at ambient conditions nearly as rapidly as the traditional high-volatility solvents they are meant to replace. Conversely, bio-based and heavy hydrocarbons did not readily volatilize, though they often are calculated as VOCs in some traditional test methods. The study suggests that regulatory standards should be reevaluated to more accurately reflect real-world emission from the use of VOC containing products.
Implications:The definition of VOC in current test methods may lead to regulations that exclude otherwise viable alternatives or allow substitutions of chemicals that may limit the environmental benefits sought in the regulation. A study was conducted to examine volatility of several compounds and a few formulated products under several current VOC test methodologies and ambient evaporation. This paper provides ample evidence to warrant a reevaluation of regulatory standards and provides a framework for progressive developments based on reasonable and scientifically justifiable definitions of VOCs.  相似文献   
188.
In Brazil, few studies on microbial content of dental solid waste and its antibiotic susceptibility are available. An effort has been made through this study to evaluate the hazardous status of dental solid waste, keeping in mind its possible role in cross-infection chain. Six samples of solid waste were collected at different times and seasons from three dental health services. The microbial content was evaluated in different culture media and atmospheric conditions, and the isolates were submitted to antibiotic susceptibility testing. A total of 766 bacterial strains were isolated and identified during the study period. Gram-positive cocci were the most frequent morphotype isolated (48.0%), followed by Gram-negative rods (46.2%), Gram-positive rods (5.0%), Gram-negative-cocci (0.4%), and Gram-positive coccobacillus (0.1%). Only two anaerobic bacteria were isolated (0.3%). The most frequently isolated species was Staphylococcus epidermidis (29.9%), followed by Stenotrophomonas maltophilia (8.2%), and Enterococcus faecalis (6.7%). High resistance rate to ampicillin was observed among Gram-negative rods (59.4%) and Gram-positive cocci (44.4%). For Gram-negative rods, high resistance was also noted to aztreonam (47.7%), cefotaxime (47.4%), ceftriaxone and cefazolin (43.7%), and ticarcillin-clavulanic acid (38.2%). Against Gram-positive cocci penicillin exhibit a higher resistance rate (45.0%), followed by ampicillin, erythromycin (27.2%), and tetracycline (22.0%). The present study demonstrated that several pathogenic bacteria are present in dental solid waste and can survive after 48 h from the waste generation time and harbor resistance profiles against several clinical recommended antibiotics.  相似文献   
189.
Linking GIS-based models to value ecosystem services in an Alpine region   总被引:12,自引:1,他引:11  
Planning frequently fails to include the valuation of public goods and services. This can have long-term negative economic consequences for a region. This is especially the case in mountainous regions such as the Alps, which depend on tourism and where land-use changes can negatively impact key ecosystem services and hence the economy. In this study, we develop a semi-automatic procedure to value ecosystem goods and services. Several existing process-based models linked to economic valuation methods are integrated into a geographic information system (GIS) platform. The model requires the input of a digital elevation model, a land-cover map, and a spatially explicit temperature dataset. These datasets are available for most regions in Europe. We illustrate the approach by valuing four ecosystem services: avalanche protection, timber production, scenic beauty, and habitat, which are supplied by the “Landschaft Davos”, an administrative district in the Swiss Alps. We compare the impacts of a human development scenario and a climate scenario on the value of these ecosystem services. Urban expansion and tourist infrastructure developments have a negative impact on scenic beauty and habitats. These impacts outweigh the benefits of the developments in the long-term. Forest expansion, predictable under a climate change scenario, favours natural avalanche protection and habitats. In general, such non-marketed benefits provided by the case-study region more than compensate for the costs of forest maintenance. Finally, we discuss the advantages and disadvantages of the approach. Despite its limitations, we show how this approach could well help decision-makers balance the impacts of different planning options on the economic accounting of a region, and guide them in selecting sustainable and economically feasible development strategies.  相似文献   
190.
From 2003 to 2006, a consortium of six European partners analysed the future of olive production systems on sloping land in the Mediterranean basin. Olive production on such land dates back to pre-Roman times, but the production systems (known by the acronym SMOPS, for "Sloping and Mountainous Olive Production Systems"), are under threat. Many are unsustainable environmentally (erosion hazard), socially (exodus of young people) or economically (high labour costs). The OLIVERO research project was possible thanks to a grant of euro1.5 million from the European Union, which gives out euro2.5 billion in subsidies annually for olive production. An extended survey conducted by the project in five sites in Portugal, Spain, Italy and Greece revealed the diversity and multifunctionality of SMOPS. Four main systems were identified as important for the future: traditional, organic, semi-intensive and intensive. The conceptual framework of OLIVERO involved six phases, ranging from the initial survey up to policy recommendations. In all phases there was intensive contact with stakeholders and institutions. End-users were identified at three levels: local, intermediate and regional, and national/international. This paper presents the highlights of the physical analysis of land and water resources, crop and land management, and economics and policies. Scenario studies gave insight into the possible future: some SMOPS will be gradually abandoned or transformed into nature conservation areas, others will exploit drip irrigation and follow the intensification patterns of agriculture in the valleys, and a third group will continue to be managed more extensively, perhaps augmenting their income with other activities (possibly off-farm) or turning to organic production systems. At the five international OLIVERO meetings held from 2003 to 2006, knowledge, experience and ideas on the future of olive production systems were intensively exchanged. A network was established for ongoing and future cooperation. Two end-user seminars were held in Matera (Italy) and Lisbon. Over 70 scientific papers have been published.  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