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   122篇
  免费   0篇
  国内免费   1篇
安全科学   6篇
废物处理   5篇
环保管理   24篇
综合类   45篇
基础理论   16篇
污染及防治   14篇
评价与监测   6篇
社会与环境   7篇
  2020年   2篇
  2019年   1篇
  2018年   2篇
  2017年   1篇
  2016年   4篇
  2015年   2篇
  2014年   5篇
  2013年   7篇
  2012年   6篇
  2011年   6篇
  2010年   1篇
  2009年   4篇
  2008年   5篇
  2007年   7篇
  2006年   6篇
  2005年   5篇
  2004年   2篇
  2003年   9篇
  2002年   4篇
  2001年   1篇
  2000年   4篇
  1999年   2篇
  1998年   2篇
  1997年   2篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1984年   3篇
  1978年   1篇
  1974年   1篇
  1973年   2篇
  1972年   2篇
  1967年   2篇
  1966年   1篇
  1965年   1篇
  1963年   1篇
  1962年   2篇
  1961年   1篇
  1960年   1篇
  1959年   1篇
  1957年   1篇
  1955年   2篇
  1953年   1篇
  1949年   1篇
  1947年   1篇
  1943年   1篇
  1942年   1篇
  1933年   1篇
  1930年   1篇
  1926年   1篇
排序方式: 共有123条查询结果,搜索用时 31 毫秒
1.
A method is described whereby dielectrophoresis of algal cells is used to perform rapid water quality analysis, specifically detecting the presence of CuSO4. The dielectric collection spectrum of the fresh water alga Selenastrum capricornutum was determined for a range of concentrations of CuSO4 from 25 mg L(-1) to 0.25 mg L(-1) for exposure times of 15 min and 18 h. In all cases increasing the concentration of CuSO4 reduced cell collection, but a step reduction was observed in collection between 2 mg L(-1) and 5 mg L(-1). This method has potential for forming a rapid, low-cost test for water quality with broad specificity and significantly reduced analysis time compared to current methods.  相似文献   
2.
3.
4.
5.
6.
The last decade has seen considerable interest in the concept of social capital and there have been a number of publications focused around the concept. A wide range of claims have been made for the analytic potential of social capital leading some to question the concept's continued value. We think that the concept still has considerable value if used in a careful and rigorous way. We further think that the concept has particular value when considering policy for sustainable development. However, just as sustainable development is a multi-faceted concept, this application requires a multi-faceted reading of social capital. Having concluded that a clearer typology of social capital is needed, we propose a threefold typology, adding the new category of 'bracing' social capital to the more commonly used distinction between 'bonding' and 'bridging' social capital. We also address the issues of what social capital can do and how it actually works, specifically in the context of policy for sustainable development.  相似文献   
7.
Call centre workplaces are in many ways a challenge to occupational health and safety. The occupation itself can be described as an IT information technology-supported, communication-intensive form of work with often unusual working hours and a high rate of part-time employment. Data on the employee turnover as well as absenteeism related to occupational disability is quite contradictory. Occupational safety and its proponents still have to find new ways into the corporate structures and cultures of this relatively new and rapidly growing branch of industry. In a 2-year research and development project, using a holistic approach and under consideration of all the relevant disciplines, call centre workplaces were studied, and organisational measures were developed and field tested by putting them into practice. Practical help was developed for a sustainable strategy for successful and healthy work in call centres.  相似文献   
8.
9.
Short-term whole sediment tests using the amphipod Corophium volutator and the polychaete Arenicola marina are now routinely used in Europe to assess the acute toxicity of marine sediments. However, there is still a need to develop longer-term assays which measure effects on sublethal endpoints that are more relevant to predicting impacts at the population level. The effect of increasing exposure times and measuring additional endpoints such as growth, on the sensitivity of these assays was investigated. The test compound used was the chemotherapeutant Ivermectin (IVM), used in aquaculture to treat sea lice infestations. IVM was found to be acutely toxic to both test organisms. Extending the lugworm test to 100 days increased sensitivity of survival by a factor of three; a significant reduction in casting rate was observed at concentrations an order of magnitude lower. This assay shows potential for detecting the sublethal effects of low concentrations of sediment contaminants. Increasing the exposure time did not seem to affect the sensitivity of the amphipod, but further method development is required.  相似文献   
10.
Even though the Selenga is the main tributary to Lake Baikal in Russia, the largest part of the Selenga River basin is located in Mongolia. It covers a region that is highly diverse, ranging from almost virgin mountain zones to densely urbanized areas and mining zones. These contrasts have a strong impact on rivers and their ecosystems. Based on two sampling campaigns (summer 2014, spring 2015), we investigated the longitudinal water quality pattern along the Selenga and its tributaries in Mongolia. While headwater regions typically had a very good water quality status, wastewater from urban areas and impacts from mining were found to be main pollution sources in the tributaries. The highest nutrient concentrations in the catchment were found in Tuul River, and severely elevated concentrations of trace elements (As, Cd, Cu, Cr, Fe, Mn, Ni, Pb, Zn), nutrients (NH4 +, NO2 ?, NO3 ?, PO4 3?), and selected major ions (SO4 2?) were found in main tributaries of Selenga River. Moreover, trace element concentrations during spring 2015 (a time when many mines had not yet started operation) were markedly lower than in summer 2014, indicating that the additional metal loads measured in summer 2014 were related to mining activities. Nevertheless, all taken water samples in 2014 and 2015 from the main channel of the Mongolian Selenga River complied with the Mongolian standard (MNS 1998) for the investigated parameters.  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