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   366篇
  免费   1篇
安全科学   3篇
废物处理   31篇
环保管理   21篇
综合类   28篇
基础理论   77篇
污染及防治   158篇
评价与监测   30篇
社会与环境   19篇
  2023年   2篇
  2022年   5篇
  2021年   7篇
  2020年   4篇
  2019年   3篇
  2018年   8篇
  2017年   4篇
  2016年   20篇
  2015年   2篇
  2014年   19篇
  2013年   40篇
  2012年   21篇
  2011年   32篇
  2010年   19篇
  2009年   14篇
  2008年   29篇
  2007年   24篇
  2006年   24篇
  2005年   15篇
  2004年   12篇
  2003年   14篇
  2002年   11篇
  2001年   7篇
  2000年   4篇
  1999年   2篇
  1998年   1篇
  1997年   2篇
  1996年   2篇
  1995年   1篇
  1994年   6篇
  1993年   2篇
  1992年   3篇
  1991年   1篇
  1990年   1篇
  1989年   3篇
  1985年   1篇
  1979年   1篇
  1975年   1篇
排序方式: 共有367条查询结果,搜索用时 62 毫秒
271.
In recent years, the concept of sustainable development (SD) has become increasingly recognized and important. Within organizations, SD is often portrayed as a balancing act and requires a combination of three elements to be considered: economy, environment, and society. Traditionally, organizational management research has been focused on economical and environmental fronts. However, social aspects are also important for organizations, especially those in emerging and developing countries. The goal of this article is to investigate the potential of Clean Development Mechanism (CDM) projects to deliver social benefits in Brazil’s hydroelectricity sector. The investigation involved the assessment of 46 registered hydro CDM projects under the Kyoto Protocol in terms of their potential impact on the envisaged social development goals. Two case studies were also examined. Results indicate that organizations managing hydroelectric initiatives in Brazil can provide the pathway toward achieving a number of important social benefits. Successful projects were found to have good community involvement and were managed by both cooperative ventures and money-making corporations. The research also identified several challenges that are hindering hydro CDM projects from delivering more social benefits and enabled a number of recommendations to be extracted for the organizations facing these challenges.  相似文献   
272.
Air temperature in several galleries of the Covadura System (Sorbas Gypsum Karst, Almería) was measured at monthly intervals over a period of 1 year. The spatial temperature distribution for each month was modeled in a geostatistical framework. The mean trend of the air temperature and the difference between each experimental temperature measurement and this trend were calculated over space and time. Both the trend and residual component were characterized using a geostatistical space-time model. A large spatial trend of the air temperature was found due to the orientation of galleries within the cave system and as a function of the distance from the main cave entrance. Kriging was used for the spatial estimation of the time covariance of the residuals. This enabled the delimitation of the cave into three zones of varying environmental risk in the event of being opened to visits by the public, according to the degree of stability of air temperature over space and time. The influence of human presence on the spatial temperature distribution was assessed using data collected during a year (2000/2001) in pilot galleries opened to the public. An average visit corresponding to August was selected comprising 16 people over a period of 53 min. This average visit influenced the spatial temperature pattern at distances of more than 90 m from the cave entrance, according to the geostatistical model adopted. Within this zone the mean thermal increment generated by human presence was estimated to be 0.26 degrees C. The spatiotemporal mathematical model of the cave air temperature has been revealed as a useful tool for the environmental management of show caves.  相似文献   
273.
The viability of anaerobic digestion of sludge from a MSW landfill leachate treatment plant, with COD values ranging between 15,000 and 19,400mg O(2)dm(-3), in an upflow anaerobic sludge blanket reactor was studied. The reactor employed had a useful capacity of 9l, operating at mesophilic temperature. Start-up of the reactor was carried out in different steps, beginning with diluted sludge and progressively increasing the amount of sludge fed into the reactor. The study was carried out over a period of 7 months. Different amounts of methanol were added to the feed, ranging between 6.75 and 1cm(3)dm(-3) of feed in order to favour the growth of methanogenic flora. The achieved biodegradation of the sludge using an upflow anaerobic sludge blanket Reactor was very high for an HRT of 9 days, obtaining decreases in COD of 84-87% by the end of the process. Purging of the digested sludge represented approximately 16% of the volume of the treated sludge.  相似文献   
274.
275.
A study was conducted on the Brigham Young University campus during January and February 2015 to identify winter-time sources of fine particulate material in Utah Valley, Utah. Fine particulate mass and components and related gas-phase species were all measured on an hourly averaged basis. Light scattering was also measured during the study. Included in the sampling was the first-time source apportionment application of a new monitoring instrument for the measurement of fine particulate organic marker compounds on an hourly averaged basis. Organic marker compounds measured included levoglucosan, dehydroabietic acid, stearic acid, pyrene, and anthracene. A total of 248 hourly averaged data sets were available for a positive matrix factorization (PMF) analysis of sources of both primary and secondary fine particulate material. A total of nine factors were identified. The presence of wood smoke emissions was associated with levoglucosan, dehydroabietic acid, and pyrene markers. Fine particulate secondary nitrate, secondary organic material, and wood smoke accounted for 90% of the fine particulate material. Fine particle light scattering was dominated by sources associated with wood smoke and secondary ammonium nitrate with associated modeled fine particulate water.

Implications: The identification of sources and secondary formation pathways leading to observed levels of PM2.5 (particulate matter with an aerodynmaic diameter <2.5 μm) is important in making regulatory decisions on pollution control. The use of organic marker compounds in this assessment has proven useful; however, data obtained on a daily, or longer, sampling schedule limit the value of the information because diurnal changes associated with emissions and secondary aerosol formation cannot be identified. A new instrument, the gas chromtography–mass spectrometry (GC-MS) organic aerosol monitor, allows for the determination on these compounds on an hourly averaged basis. The demonstrated potential value of hourly averaged data in a source apportionment analysis indicates that significant improvement in the data used for making regulatory decisions is possible.  相似文献   

276.
Environmental Science and Pollution Research - Mosquitoes (Diptera: Culicidae) are vectors of important parasites and pathogens causing death, poverty and social disability worldwide. The overuse...  相似文献   
277.
Environmental Science and Pollution Research - Acinetobacter guillouiae SFC 500-1A, a native bacterial strain isolated from tannery sediments, is able to simultaneously remove high concentrations...  相似文献   
278.
The Svalbard Global Seed Vault provides a backup of seed collections from genebanks around the world. It’s unique character has made it iconic in the public imagination as a ‘Noah’s Ark’ for crop plants. Its remote location and strict controls on access have, however, also lent it an air of mystery, swirling with conspiracy theories. In this paper, I first clarify the aims of the Vault, the history of its development and the policies and practices of its current operation. Given concerns around its potential links to the biotechnology industry, I go on to ask whether GM crops are currently stored in the Vault. Presenting several reasons for why GM crops are formally excluded, while indicating the potential for both change and unintentional contamination, I am compelled to question whether GM crops should be excluded. Answering this requires an interrogation of their potential conservation value as modern contributors to crop biodiversity. In exploring this issue, I suggest that there has been surprisingly little discussion of the moral status and conservation value of bio-technological crop plants and indeed, of how we care for all the techno-lifeforms we are currently engaged in co-creating. I suggest that these are becoming important issues as biotechnological techniques and applications begin to rapidly evolve and diversify (e.g. through genome editing and synthetic biology). Emphasizing the scope for a refreshed interdisciplinary research agenda exploring the interface between biotechnology and biodiversity conservation, I conclude the article by proposing new concepts of synbiodiversity and symbiodiversity to encourage further debate.  相似文献   
279.
This paper reports a study of the anaerobic biodegradation of non-ionic surfactants alkyl polyglucosides applying the method by measurement of the biogas production in digested sludge. Three alkyl polyglucosides with different length alkyl chain and degree of polymerization of the glucose units were tested. The influence of their structural parameters was evaluated, and the characteristics parameters of the anaerobic biodegradation were determined. Results show that alkyl polyglucosides, at the standard initial concentration of 100 mgC L?1, are not completely biodegradable in anaerobic conditions because they inhibit the biogas production. The alkyl polyglucoside having the shortest alkyl chain showed the fastest biodegradability and reached the higher percentage of final mineralization. The anaerobic process was well adjusted to a pseudo first-order equation using the carbon produced as gas during the test; also, kinetics parameters and a global rate constant for all the involved metabolic process were determined. This modeling is helpful to evaluate the biodegradation or the persistence of alkyl polyglucosides under anaerobic conditions in the environment and in the wastewater treatment.  相似文献   
280.
Environmental Science and Pollution Research - This study provides an analysis of the spatial distribution and trends of NO, NO2 and O3 concentrations in Portugal between 1995 and 2010....  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