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   206篇
  免费   5篇
  国内免费   4篇
安全科学   7篇
废物处理   11篇
环保管理   22篇
综合类   21篇
基础理论   44篇
污染及防治   73篇
评价与监测   22篇
社会与环境   14篇
灾害及防治   1篇
  2023年   4篇
  2022年   17篇
  2021年   12篇
  2020年   4篇
  2019年   8篇
  2018年   12篇
  2017年   17篇
  2016年   17篇
  2015年   10篇
  2014年   10篇
  2013年   30篇
  2012年   10篇
  2011年   11篇
  2010年   7篇
  2009年   9篇
  2008年   6篇
  2007年   7篇
  2006年   6篇
  2005年   2篇
  2004年   6篇
  2003年   2篇
  2002年   1篇
  1997年   2篇
  1995年   1篇
  1993年   1篇
  1991年   2篇
  1976年   1篇
排序方式: 共有215条查询结果,搜索用时 937 毫秒
81.
Sustainability-oriented undertakings employ a multitude of different definitions and understandings of the term sustainable development. Against this background, the question of which sustainability goals to refer to at project level must be posed. This article discusses this question using the example of research on land use issues. It presents a qualitative in-depth empirical analysis of the underlying sustainability understanding of research projects, and identifies crucial characteristics of the ways researchers deal with the respective normative goals. The notions of sustainable development advanced by such projects featured different foci with respect to the overall meaning of the concept and were influenced by diverse actor and stakeholder perspectives. Further, the identified sustainability conceptions were deliberated on to different extents, and also differed with respect to whether they were explicit or contextualized. Most importantly, the projects differed in how they broached the issue of sustainability goals as part of research. The findings were used to develop a set of guidelines that clarifies how research can be related successfully to the societal vision of sustainable development. The guidelines draw conceptually on general requirements for appropriate sustainability conceptions derived from the Brundtland definition. They offer a tool for reflecting on one’s assumptions with respect to sustainability goals at any stage of research, which is crucial for advancing the seminal field of sustainability science.  相似文献   
82.
83.
This study represents the first use of Leucozonia nassa (Mollusca-Gastropoda) in a program of long-term monitoring. Specimens of L. nassa were collected between 2006 and 2014 and analyzed for the occurrence of imposex in two areas in Southeastern Brazil, one control area and another characterized by the presence of many ports and marinas. Imposex was evaluated in nine sites based on the percentage of females exhibiting imposex (I%), relative penis length index and vas deferens sequence index, classical indices to evaluate tributyltin (TBT) impacts. Moreover, this study uses for the first time in a tropical environment the ecological quality ratio (EQR), an approach to verify the imposex levels as an indicator of the impact by organotin compounds according to the EU Water Framework Directive. The results confirm the occurrence of high levels of imposex in L. nassa with all the indices evaluated. Furthermore, the results also indicate that, despite the international ban, antifouling paints based on TBT are still possibly used in Brazil. In addition, this study shows that L. nassa has the characteristics that make it a suitable bioindicator to monitor TBT pollution, and that the use of the EQR may create important data regarding this problem.  相似文献   
84.
The objective of this study was to determine the main patterns and factors influencing food transition in riverine people in the Brazilian Amazon. Through interviews with a semi-structured questionnaire, we inferred their food habits and provide information about general demographic, socioeconomic, resource use and environmental context. Data from the questionnaires were categorized and analyzed using a logistic regression model to assess the relative influence of socioeconomic and environment factors on the local diet. Based on a logistic regression data analysis, it was found a greater consumption of processed food significantly associated with multiple factors such as market participation, sex (female and male), government aid to forest conservation and environment context (upland and wetland). Although the local diet is composed mainly of local resources such as fish and cassava flour, increasing incomes due to direct government subsidy programs and marketing of cassava flour have influenced these local practices and habits. Through the analysis of factors influencing food transition, it was possible to evaluate those having the greatest effect on this Amazon region and propose an alternative method to subsidy food policy grounded in local opinion surveys.  相似文献   
85.
Forests cover approximately one‐third of Central Europe. Oak (Quercus) and European beech (Fagus sylvatica) are considered the natural dominants at low and middle elevations, respectively. Many coniferous forests (especially of Picea abies) occur primarily at midelevations, but these are thought to have resulted from forestry plantations planted over the past 200 years. Nature conservation and forestry policy seek to promote broadleaved trees over conifers. However, there are discrepancies between conservation guidelines (included in Natura 2000) and historical and palaeoecological data with regard to the distribution of conifers. Our aim was to bring new evidence to the debate on the conservation of conifers versus broadleaved trees at midelevations in Central Europe. We created a vegetation and land‐cover model based on pollen data for a highland area of 11,300 km2 in the Czech Republic and assessed tree species composition in the forests before the onset of modern forestry based on 18th‐century archival sources. Conifers dominated the study region throughout the entire Holocene (approximately 40–60% of the area). Broadleaved trees were present in a much smaller area than envisaged by current ideas of natural vegetation. Rather than casting doubt on the principles of Central European nature conservation in general, our results highlight the necessity of detailed regional investigations and the importance of historical data in challenging established notions on the natural distribution of tree species.  相似文献   
86.
87.
During the last 10 years, high atmospheric concentrations of airborne particles recorded in the Mexico City metropolitan area have caused concern because of their potential harmful effects on human health. Four monitoring campaigns have been carried out in the Mexico City metropolitan area during 2000-2002 at three sites: (1) Xalostoc, located in an industrial region; (2) La Merced, located in a commercial area; and (3) Pedregal, located in a residential area. Results of gravimetric and chemical analyses of 330 samples of particulate matter (PM) with an aerodynamic diameter less than 2.5 microm (PM2.5) and PM with an aerodynamic diameter less than 10 microm (PM10) indicate that (1) PM2.5/PM10 average ratios were 0.42, 0.46, and 0.52 for Xalostoc, La Merced, and Pedregal, respectively; (2) the highest PM2.5 and PM10 concentrations were found at the industrial site; (3) PM2.5 and PM10 concentrations were lower at nighttime; (4) PM2.5 and PM10 spatial averages concentrations were 35 and 76 microg/m3, respectively; and (5) when the PM2.5 standard was exceeded, nitrate, sulfate, ammonium, organic carbon, and elemental carbon concentrations were high. Twenty-four hour averaged PM2.5 concentrations in Mexico City and Sao Paulo were similar to those recorded in the 1980s in Los Angeles. PM10 concentrations were comparable in Sao Paulo and Mexico City but 3-fold lower than those found in Santiago.  相似文献   
88.
89.
90.
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