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   143篇
  免费   0篇
  国内免费   1篇
安全科学   4篇
废物处理   3篇
环保管理   10篇
综合类   43篇
基础理论   39篇
污染及防治   37篇
评价与监测   6篇
社会与环境   2篇
  2022年   1篇
  2021年   3篇
  2020年   3篇
  2019年   5篇
  2018年   5篇
  2017年   2篇
  2016年   4篇
  2015年   4篇
  2014年   7篇
  2013年   10篇
  2012年   3篇
  2011年   7篇
  2010年   13篇
  2009年   5篇
  2008年   4篇
  2007年   13篇
  2006年   3篇
  2005年   4篇
  2004年   2篇
  2003年   3篇
  2002年   2篇
  2001年   5篇
  2000年   1篇
  1999年   1篇
  1998年   1篇
  1997年   3篇
  1996年   1篇
  1995年   5篇
  1992年   1篇
  1991年   2篇
  1985年   1篇
  1963年   2篇
  1962年   1篇
  1958年   1篇
  1956年   3篇
  1955年   2篇
  1950年   1篇
  1942年   1篇
  1941年   1篇
  1938年   1篇
  1937年   1篇
  1934年   3篇
  1933年   1篇
  1928年   1篇
  1926年   1篇
排序方式: 共有144条查询结果,搜索用时 15 毫秒
61.
62.
Levels of 2,3,7,8-TCDD were measured in more than one hundred soil samples collected around a TCP-producing plant. Some other materials were also tested. A suitable method for determination of 2,3,7,8-TCDD in heavy contaminated soils was developed. The levels obtained are presented.  相似文献   
63.
64.
The paper differentiates approaches in technology (end-of-pipe, cleaner production, industrial ecology, zero emission and eco-social-tech) and compares them in respect to the problem solving capacity on the ecological as well as social dimension by showing the eco-impact reduction and job creation. Eco-social-tech represents the approach with highest problem solution as it is based on "eco-social market economy", which will the replace free market economy. The deep background of these innovations is "ecosophy", the wisdom of nature, which serves as guideline for eco-restructuring the world.  相似文献   
65.
- DOI: http:/dx.doi.org/10.1065/espr2005.06.262 Goal, Scope and Background The anthropogenic environmental emissions of chloroacetic acids and volatile organochlorines have been under scrutiny in recent years because the two compound groups are suspected to contribute to forest dieback and stratospheric ozone destruction, respectively. The two organochlorine groups are linked because the atmospheric photochemical oxidation of some volatile organochlorine compounds is one source of phytotoxic chloroacetic acids in the environment. Moreover, both groups are produced in higher amounts by natural chlorination of organic matter, e.g. by soil microorganisms, marine macroalgae and salt lake bacteria, and show similar metabolism pathways. Elucidating the origin and fate of these organohalogens is necessary to implement actions to counteract environmental problems caused by these compounds. Main Features While the anthropogenic sources of chloroacetic acids and volatile organochlorines are relatively well-known and within human control, knowledge of relevant natural processes is scarce and fragmented. This article reviews current knowledge on natural formation and degradation processes of chloroacetic acids and volatile organochlorines in forest soils, with particular emphasis on processes in the rhizosphere, and discusses future studies necessary to understand the role of forest soils in the formation and degradation of these compounds. Results and Discussion Reviewing the present knowledge of the natural formation and degradation processes of chloroacetic acids and volatile organochlorines in forest soil has revealed gaps in knowledge regarding the actual mechanisms behind these processes. In particular, there remains insufficient quantification of reliable budgets and rates of formation and degradation of chloroacetic acids and volatile organochlorines in forest soil (both biotic and abiotic processes) to evaluate the strength of forest ecosystems regarding the emission and uptake of chloroacetic acids and volatile organochlorines, both on a regional scale and on a global scale. Conclusion It is concluded that the overall role of forest soil as a source and/or sink for chloroacetic acids and volatile organochlorines is still unclear; the available laboratory and field data reveal only bits of the puzzle. Detailed knowledge of the natural degradation and formation processes in forest soil is important to evaluate the strength of forest ecosystems for the emission and uptake of chloroacetic acids and volatile organochlorines, both on a regional scale and on a global scale. Recommendation and Perspective As the natural formation and degradation processes of chloroacetic acids and volatile organochlorines in forest soil can be influenced by human activities, evaluation of the extent of this influence will help to identify what future actions are needed to reduce human influences and thus prevent further damage to the environment and to human health caused by these compounds.  相似文献   
66.
Ecotoxicological investigations focus on biological systems and their response to chemically induced stress. Experimental techniques are much more developed than deterministic dynamic modelling. In this methodological contribution a technique is presented, based on lattice theory. This technique, also calledHasse diagram technique, allows data analysis with respect to comparative evaluation. Hasse diagrams are used
  • ? to suggest a possible measure of microbial diversity,
  • ? to analyze dependencies between phospholipid fatty acids and simple geochemical parameters on an ordinal scale and
  • ? to visualise complex results of interactions of humic substances with xenobiotics.
  •   相似文献   
    67.
    Environmental and Ecological Statistics - Habitat modifications driven by human impact and climate change may influence species distribution, particularly in aquatic environments. Niche-based...  相似文献   
    68.
    69.
    70.
    Ecological theory predicts that low productivity systems should have low biodiversity. However, despite the oligotrophic status of the Gulf of Aqaba (Northern Red Sea) ciliate species richness was unexpectedly high. In addition, phytoplankton, as main ciliate prey, was made up by only few genera, indicating a significant niche overlap among the grazers. Up to 97% of the ciliates were from the same taxonomic group and of the same size range, implying very similar food niches. Ciliate diversity was highest at times of lowest chlorophyll concentrations, during the period of stable abiotic conditions, but relatively high genetic diversity within the ciliate prey, notably among the cyanobacteria Synechococcus and Prochlorococcus. In the absence of disturbance and with little predation pressure, the alternate explanations for the observed ciliate diversity are either very fine niche partitioning by the ciliates, or their competitive equivalence resulting in a random assortment of species immigrating from a larger metacommunity, in accordance with Hubbell’s, (The unified neutral theory of biodiversity and biogeography. Princeton University Press, Princeton, 2001) neutral model. While the use of species abundance distributions (SAD’s) is far from definitive, the theoretical SAD’s that best fit the Gulf of Aqaba ciliate data was most often not that expected by neutral theory.  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