首页 | 官方网站   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   395篇
  免费   6篇
  国内免费   5篇
环境安全   406篇
  2023年   8篇
  2022年   16篇
  2021年   13篇
  2020年   6篇
  2019年   9篇
  2018年   13篇
  2017年   17篇
  2016年   21篇
  2015年   12篇
  2014年   16篇
  2013年   23篇
  2012年   34篇
  2011年   21篇
  2010年   10篇
  2009年   20篇
  2008年   19篇
  2007年   19篇
  2006年   14篇
  2005年   12篇
  2004年   10篇
  2003年   13篇
  2002年   10篇
  2001年   6篇
  2000年   2篇
  1998年   2篇
  1997年   6篇
  1995年   2篇
  1994年   5篇
  1992年   2篇
  1991年   4篇
  1990年   2篇
  1989年   2篇
  1964年   2篇
  1961年   1篇
  1959年   2篇
  1957年   2篇
  1956年   1篇
  1954年   1篇
  1948年   1篇
  1932年   1篇
  1931年   1篇
  1925年   2篇
  1924年   2篇
  1923年   2篇
  1921年   3篇
  1920年   1篇
  1919年   1篇
  1918年   2篇
  1917年   1篇
  1914年   1篇
排序方式: 共有406条查询结果,搜索用时 15 毫秒
1.
The technique of thermal desorption (TD)–GC/MS was evaluated for measuring airborne, 4–6 ring polycyclic aromatic hydrocarbons (PAHs) collected onto quartz filters. TD provides a more readily automated and sensitive alternative to traditional solvent extraction, decreasing the time/cost of analysis and reducing the risk of analyte loss or sample contamination. The developed method was successfully applied to the analysis of PAH standard solutions loaded on sorbent tubes packed with quartz wool and the graphitized carbon black sorbent Carbograph2. The optimized method showed high desorption efficiency over the whole range of target PAHs with good precision, linearity and sensitivity. The proposed method was verified on an urban dust Standard Reference Material (SRM 1649a); the experimentally determined concentrations agreed with the certified ranges (95% confidence limit) for all target compounds except benzo[a]anthracene, which fell just outside the narrow certified range. The desorption efficiency and the reproducibility of the method was evaluated by analysing pieces of real sample filters sampled from urban air for a period of 24 h. The results confirmed the homogeneity of the filter and showed high recovery efficiencies for all target PAHs.  相似文献   
2.
The objective of this article is to understand how the promotion of clusters of small economic agents in the gem sector has brought some improvements in the economic, social and environmental conditions in the mining sector and activities related to it. The research provides policy and theoretical contributions to the field of gem production, as well as enhances understanding of the under researched opal production in Brazil. It argues that government funding and technical support dedicated to the development of mining clusters, i.e. working with small economic agents as a whole and not individually, could promote not only more economic development, but also effectively incorporate social and environmental issues, such as workers safety, water management and tailings recycling. The argument is based on an evaluation of environmental, economic, social and institutional aspects of the opal mining cluster in Pedro II municipality, Piauí state. The results suggest that some formalisation of existing practices and adequate policies have triggered innovation with some positive effects on the performance of artisanal mining. Nevertheless, there are indications that if decision-makers plan to make this cluster more sustainable, they will have to include other issues in the debate including developing substituting economic activities.  相似文献   
3.
Vulnerability assessment is increasingly recognised as a starting point to identify climate adaptation needs and improve adaptive capacity. However, vulnerability assessments are challenging because of the complexity of multifaceted biophysical, human and institutional factors, interacting at different scales and levels within socio-ecological systems. Using a participatory approach across levels and genders, this paper explores the vulnerability of livestock- and forest-based livelihoods to climate variability and change in Lake Faguibine, northern Mali, where drastic ecological, political and social changes have occurred. Our results show that the distribution of vulnerabilities within livelihoods and groups shifted when the ecosystem evolved from a lake to a forest. New vulnerability drivers have emerged, related to resources availability, access and power relations. In addition, political interests and psychological barriers hinder the local transition to an equitable and sustainable use of forest ecosystem services. Divergent perceptions, social identities, interests and power explained why different actors—governmental and non-governmental, men and women, local, sub-national and national—differed in their vulnerability assessments. This is exemplified in the way actors at different levels and of different gender analysed the effects of herders’ mobility and in the way women analysed men’s migration. This case study confirms the need for participatory and gender-sensitive vulnerability assessments across different scales and levels that consider the interaction between socio-ecological systems and the dynamics and distribution of vulnerability across different social sub-systems.  相似文献   
4.
Large-scale studies are essential to assess the emission patterns and spatial distribution of organohalogenated pollutants (OHPs) in the environment. Bird eggs have several advantages compared to other environmental media which have previously been used to map the distribution of OHPs. In this study, large-scale geographical variation in the occurrence of OHPs, such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs), was investigated throughout Europe using eggs of a terrestrial residential passerine species, the great tit (Parus major). Great tit eggs from 22 sampling sites, involving urban, rural and remote areas, in 14 European countries were collected and analysed (5-8 eggs per sampling site). The environmentally most important congeners/compounds of the analysed pollutants were detectable in all sampling locations. For PCBs, PBDEs and OCPs, no clear geographical contamination pattern was found. Sum PCB levels ranged from 143 ng/g lipid weight (lw) to 3660 ng/g lw. As expected, PCB concentrations were significantly higher in the sampled urban compared to the remote locations. However, the urban locations did not show significantly higher concentrations compared to the rural locations. Sum PBDEs ranged from 4.0 ng/g lw to 136 ng/g lw. PBDEs were significantly higher in the urbanized sampling locations compared to the other locations. The significant, positive correlation between PCB and PBDE concentrations suggests similar spatial exposure and/or mechanisms of accumulation. Significantly higher levels of OCPs (sum OCPs ranging from 191 ng/g lw to 7830 ng/g lw) were detected in rural sampling locations. Contamination profiles of PCBs, PBDEs and OCPs differed also among the sampling locations, which may be due to local usage and contamination sources. The higher variance among sampling locations for the PCBs and OCPs, suggests that local contamination sources are more important for the PCBs and OCPs compared to the PBDEs. To our knowledge, this is the first study in which bird eggs were used as a monitoring tool for OHPs on such a large geographical scale.  相似文献   
5.
Using the focusing event framework, a comprehensive analysis of private households’ and businesses’ preparedness was undertaken in the aftermath of the 2002 and 2006 flood events on the Elbe River in Germany. In August 2002, preparedness of households (n = 235) and businesses (n = 103) was low: 30% of the households and 54% of the businesses took no precautionary measures before the flood event. Many undertaken emergency measures were ineffective, since only 26% of all households knew how to react when the flood warning came, and only 9% of businesses had an emergency plan in place. Due to this extreme flood, double-loop learning occurred in many households and businesses, so that many did implement precautionary measures. The distribution of adopted precautionary measures for households fits well to Preisendörfer’s low-cost hypothesis, but does not apply for businesses. Only 10% of the households (n = 112), but still 29% of the businesses (n = 41) were unprepared before the flood in 2006. Significant improvement in flood preparedness activities is still necessary. Particularly for businesses, regulatory programs and programs encouraging proactive behaviour should be implemented. The focusing event framework proofed to be a useful tool for a differentiated analysis of the responses to and learning due to a disaster also in the commercial and private sector.  相似文献   
6.
7.
8.
A vacuum pyrolysis process was used for the remediation of hydrocarbon–contaminated soils from “Les Vidangeurs de Montréal” site in Mascouche in the province of Québec, near Montréal. Ten samples were tested on a laboratory scale batch reactor, and one sample was tested on a prototype process development unit. The process is simple, efficient, reliable, and economically competitive with other existing technologies. The vacuum pyrolysis process efficiently treated soils contaminated with a variety of pollution levels and types, irrespective of the soil matrix, providing treated soils meeting the A criterion (noncontaminated, residential level) of the Ministry of Environment Québec (MENVIQ). The pyrolytic oil and the noncondensable pyrolytic gases can be used as makeup fuel in the process, because they have a high calorific value and their combustion should not pose any emission problems. The waterphase effluent must be treated before discharge.  相似文献   
9.
10.
The popularization of mobile phones, combined with a technological evolution, means a large number of scrap and obsolete equipment are discarded every year, thereby causing economic losses and environmental pollution. In the present study, the printed wiring boards scrap of mobile phones were characterized in order to recycle some of the device components, using techniques of mechanical processing, hydrometallurgy and electrometallurgy. The use of the techniques of mechanical processing (milling, particle size classification, magnetic and electrostatic separation) was an efficient alternative to obtain a concentrated fraction (mainly iron in the magnetic fraction and copper in the conductive fraction) and another fraction containing polymers and ceramics. At the end of mechanical processing, a concentrated fraction of metals could be obtained with an average concentration of 60% copper. This concentrated fraction in metals was dissolved in aqua regia and sent to electrowinning to recover 92% of the dissolved copper. The obtained cathodes have a copper content above 95%, which demonstrates the technical feasibility of recovery of copper using the techniques of mechanical processing, hydrometallurgy and electrometallurgy.  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-23

京公网安备 11010802026262号