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   458篇
  免费   6篇
  国内免费   14篇
安全科学   78篇
废物处理   15篇
环保管理   84篇
综合类   166篇
基础理论   29篇
污染及防治   69篇
评价与监测   22篇
社会与环境   9篇
灾害及防治   6篇
  2023年   8篇
  2022年   4篇
  2021年   5篇
  2020年   13篇
  2019年   4篇
  2017年   6篇
  2016年   12篇
  2015年   12篇
  2014年   13篇
  2013年   35篇
  2012年   13篇
  2011年   22篇
  2010年   18篇
  2009年   21篇
  2008年   20篇
  2007年   19篇
  2006年   31篇
  2005年   13篇
  2004年   23篇
  2003年   39篇
  2002年   17篇
  2001年   15篇
  2000年   21篇
  1999年   25篇
  1998年   9篇
  1997年   9篇
  1996年   10篇
  1995年   5篇
  1994年   17篇
  1993年   8篇
  1992年   3篇
  1991年   1篇
  1989年   1篇
  1985年   1篇
  1984年   3篇
  1981年   1篇
  1978年   1篇
排序方式: 共有478条查询结果,搜索用时 31 毫秒
441.
浅谈水面溢油污染防治技术及其应用   总被引:4,自引:0,他引:4  
指出水面溢油污染的产生及危害,并提出溢油污染的防治技术和应用。  相似文献   
442.
采用破乳、加热、离心、压谊的流程来处理炼油厂的浮选渣。研究结果表明:该流程不仅脱水效果显著,而且还能回收大量污油,达到了变废为宝的效果.  相似文献   
443.
含硫污水油—水旋流分离技术研究   总被引:6,自引:0,他引:6  
介绍了自行研究开发的适用于炼油含硫污水除油的新型旋流器 ,利用这种高效、节能的污水除油技术 ,油珠的最小分离粒径为 1 0 μm,平均除油效率为 66%。  相似文献   
444.
The conception, design, and implementation of sustainable development strategies in an organization aims at meeting and balancing economic, social, and environmental needs of internal and external stakeholders. While the principles and fundamentals of sustainability assist during the conception and design phases, the implementation process of management strategies – impacted directly or indirectly by internal and external factors – may identify areas of competitive advantages or challenges that would impede the projects and organizations’ performance targets. An organization is not an isolated entity and its performance is often compared against others in the market arena; therefore, assessment tools, benchmarking processes, and reporting strategies become essential for the understanding of the efforts made towards the implementation of plan, policies, and programs at the organization and project levels. A framework for a hybrid process-criterion benchmarking methodology is proposed in this paper. The framework integrates the Rank Xerox benchmarking process and the Wa-Pa-Su project sustainability rating system assessment methodology. The proposed hybrid process-criterion benchmarking methodology encourages the diversification in the development and implementation of sustainable and environmental rating systems in industry contexts (e.g., oil and gas, mining, heavy industrial, and energy) and aims for the improvement of existing sustainability performance assessment and reporting practices. It also assists the quantitative assessment process of advances and/or setbacks in sustainability performance and the implementation of continuous performance improvement programs.  相似文献   
445.
Economic and Ecological Outcomes of Flexible Biodiversity Offset Systems   总被引:1,自引:0,他引:1  
The commonly expressed goal of biodiversity offsets is to achieve no net loss of specific biological features affected by development. However, strict equivalency requirements may complicate trading of offset credits, increase costs due to restricted offset placement options, and force offset activities to focus on features that may not represent regional conservation priorities. Using the oil sands industry of Alberta, Canada, as a case study, we evaluated the economic and ecological performance of alternative offset systems targeting either ecologically equivalent areas (vegetation types) or regional conservation priorities (caribou and the Dry Mixedwood natural subregion). Exchanging dissimilar biodiversity elements requires assessment via a generalized metric; we used an empirically derived index of biodiversity intactness to link offsets with losses incurred by development. We considered 2 offset activities: land protection, with costs estimated as the net present value of profits of petroleum and timber resources to be paid as compensation to resource tenure holders, and restoration of anthropogenic footprint, with costs estimated from existing restoration projects. We used the spatial optimization tool MARXAN to develop hypothetical offset networks that met either the equivalent‐vegetation or conservation‐priority targets. Networks that required offsetting equivalent vegetation cost 2–17 times more than priority‐focused networks. This finding calls into question the prudence of equivalency‐based systems, particularly in relatively undeveloped jurisdictions, where conservation focuses on limiting and directing future losses. Priority‐focused offsets may offer benefits to industry and environmental stakeholders by allowing for lower‐cost conservation of valued ecological features and may invite discussion on what land‐use trade‐offs are acceptable when trading biodiversity via offsets. Resultados Económicos y Ecológicos de Sistemas de Compensación de Biodiversidad Flexible Habib et al.  相似文献   
446.
Elaeagnus umbellata, a member of the Elaeagnaceae family, is native to Pakistan, China, India, Korea, and Japan. It is found commonly at altitudes ranging from 1200 to 2100 m and thrives on eroded and degraded land due to its ability to fix nitrogen. The plant also grows under variable pH (4–8) and drought, and is used locally as fuel wood, fencing, fodder, basket making, and shelterbelts. The fruit of the plant is well known for its essential nutrients and medicinal compounds such as vitamins, minerals, essential fatty acids, carotenoids (lycopene), soluble solids, and sugars. Medicinally, it is widely believed to protect against myocardial infections, pulmonary infections, and various forms of cancers. Ten ecotypes from variable microclimatic conditions were investigated for their morphological, molecular and biochemical diversity improvement and commercialization purposes. Comparisons and disabilities indicated significant variability in terms of morphological (plant height, number of branches, thorn size and number, leaf area, fruit size, 100 fruit weight, and yield), molecular (SDS-PAGE), and micro- and macronutrient (vitamin C, Fe, mg, P, Na, K, essential oils, and sugar) bases among the ecotypes. This variability will be helpful in developing commercial varieties of the plant utilizing the conventional techniques of selection and hybridization for economic activities. The plant has ample quantities of multiple micronutrients, thus indicating their expression through a powerful promoter at one place (fruit mesocarp). Efforts to identify and isolate the micronutrient genes (vitamin A, C, E, and Fe), the deficiency of which causes malnutrition and disabilities within the population of developing countries. Micronutrient genes have also been initiated for their characterization and future transformation into staple food crops for stable bio-fortification.  相似文献   
447.
Tansel B  Pascual B 《Chemosphere》2011,85(7):1182-1186
In coastal areas, estuaries, and inland waters, dispersant use after oil spills is not allowed due to sensitivity of the ecosystems. The purpose of this study was to investigate the removal of emulsified fuel oils from brackish and pond water by dissolved air flotation (DAF) with and without use of coagulants. Experiments were conducted with a 60 L DAF system. Fuel oil-water emulsions were prepared with regular unleaded gasoline, jet fuel, and diesel fuel mixed at 1:1:1 (v/v/v) ratio. Batch and continuous runs were conducted at air pressurization of 354.6 kPa. During both batch and continuous modes, significant petroleum hydrocarbon (PHC) removal was achieved within 10 min. Coagulant addition initially increased the PHC removal by about 5-15%. However, effectiveness of the coagulant was not significant after 20 min due to breakage of the aggregates. In general, the pond water had higher PHC removal than the brackish water. With longer run times, PHC removal improved slightly and the effluent contained increasing fractions of higher molecular weight compounds indicating that PHC removal was due to both DAF and stripping processes. Results indicate that DAF process can be effective both with and without the use of coagulants for removing PHCs from brackish and pond waters.  相似文献   
448.
Hassler B 《Ambio》2011,40(2):170-178
Marine governance of oil transportation is complex. Due to difficulties in effectively monitoring procedures on vessels en voyage, incentives to save costs by not following established regulations on issues such as cleaning of tanks, crew size, and safe navigation may be substantial. The issue of problem structure is placed in focus, that is, to what degree the specific characteristics and complexity of intentional versus accidental oil spill risks affect institutional responses. It is shown that whereas the risk of accidental oil spills primarily has been met by technical requirements on the vessels in combination with Port State control, attempts have been made to curb intentional pollution by for example increased surveillance and smart governance mechanisms such as the No-Special-Fee system. It is suggested that environmental safety could be improved by increased use of smart governance mechanisms tightly adapted to key actors’ incentives to alter behavior in preferable directions.  相似文献   
449.
A previously reported acute temperature dependency for the effective removal of tarry residue from feather clusters, utilising magnetic particles, has also been demonstrated to occur for the plumage of whole birds, whereby a maximum removal of up to 96% may be achieved. The experimental design allows an approximate equilibrium constant, for the distribution of contaminant between the residue and the magnetic particles, to be estimated at each temperature. This allows the thermodynamics of the process to be examined via application of the van't Hoff equation, suggesting an explanation for the phenomenon.  相似文献   
450.
For environmental control purposes, floating oil spills in harbours, off shore areas and their sources must often be identified. Pattern recognition, applied to JR spectrophotometric data (600-2000 cm m 1 range), and to chromatographic data ( n -alkanes) for the spill and various suspected sources such as oil and fuels from ships bunkers and harbour installations, can lead to definite conclusions; particularly after artificial weathering formula are used. The software application provides quick and accurate identification of the pollution source. The identification algorithm has a learning stage in which the user creates a minimal database. This database has a tree structure with classes (fuels, crude, etc.) and members representing samples from already known sources. A sample contains JR and chromatographic data and information of the originating source. A larger database means more knowledge, which conveys a better identification. When the origin of an unknown sample is searched for, the software looks for the best match through the database and displays the results in two lists; sorted by calculated similarity. One list displays the classes in which the unknown sample could be included and the other displays the possible sources. An extra check can be done by visual inspection of the overlapped graphics (unknown sample and each of the identified sources).  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