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   104篇
  免费   3篇
  国内免费   3篇
安全科学   1篇
废物处理   5篇
环保管理   18篇
综合类   35篇
基础理论   9篇
污染及防治   34篇
评价与监测   4篇
社会与环境   3篇
灾害及防治   1篇
  2022年   2篇
  2020年   3篇
  2019年   2篇
  2018年   2篇
  2016年   1篇
  2015年   3篇
  2014年   2篇
  2013年   17篇
  2012年   2篇
  2011年   3篇
  2010年   2篇
  2009年   3篇
  2008年   4篇
  2007年   2篇
  2006年   3篇
  2005年   4篇
  2004年   2篇
  2003年   4篇
  2002年   1篇
  2000年   5篇
  1999年   1篇
  1998年   2篇
  1997年   1篇
  1993年   1篇
  1992年   1篇
  1990年   1篇
  1988年   1篇
  1986年   6篇
  1984年   2篇
  1973年   2篇
  1970年   1篇
  1965年   1篇
  1964年   1篇
  1961年   1篇
  1959年   1篇
  1958年   2篇
  1957年   1篇
  1956年   2篇
  1955年   1篇
  1934年   1篇
  1933年   3篇
  1932年   3篇
  1931年   1篇
  1929年   1篇
  1928年   1篇
  1927年   1篇
  1925年   1篇
  1923年   1篇
  1918年   1篇
排序方式: 共有110条查询结果,搜索用时 531 毫秒
81.
82.
83.
84.
85.
86.
87.
Dugout canoes are traditional boat types made from a single tree trunk. This type of boat can reveal unique connections between forest and fisheries in coastal areas: their construction and the species used depend on the local ecological knowledge of artisans and the plant resources available and are also influenced by the type of fisheries in which the canoe will be used. Our objective was to analyze how dugout canoes are constructed, maintained, and currently used in the central coastal region of Santa Catarina, Brazil. The study emphasizes the interaction between the use of forest resources and artisanal fishing in this coastal environment. The data collected were based on interviews with 30 artisans and participant observation. Schizolobium parahyba (Vell.) Blake, Ocotea porosa (Nees & Mart.) Barroso, Ocotea Aubl../Nectandra Roll. Ex Rottb., and Aspidosperma Mart. & Zucc. are the main taxa used to construct the canoes. Many canoe sizes are used, and based on the boat type, the trunk diameters needed to construct them varies from 0.6 to 2.9 m and trunk heights from 4 to 10 m. Different types of canoe are used according to the type of fishing and especially to the environment conditions. The construction of canoes in the region has decreased due to difficulties in acquiring wood, changes in fishing activities, and reasons related to labor and apprenticeship, all causes related to modernization of the society and urban growth. The knowledge of plant species used can contribute to shape policies to improve forest management. The survival of cultural practices in artisanal fishing communities should be stimulated in sustainable development programs, and it involves maintaining ecological and technical knowledge related to fishing and the plant resources used to manufacture and maintain fishing equipment.  相似文献   
88.
89.
90.
To evaluate the validity of fixed-site fine particle levels as exposure surrogates in air pollution epidemiology, we considered four indicator groups: (1) PM2.5 total mass concentrations, (2) sulfur and potassium for regional air pollution, (3) lead and bromine for traffic-related particles, and (4) calcium for crustal particles. Using data from the European EXPOLIS (Air Pollution Exposure Distribution within Adult Urban Populations in Europe) study, we assessed the associations between 48-hr personal exposures and home outdoor levels of the indicators. Furthermore, within-city variability of fine particle levels was evaluated. Personal exposures to PM2.5 mass were not correlated to corresponding home outdoor levels (n = 44, rSpearman (Sp) = 0.07). In the group reporting neither relevant indoor sources nor relevant activities, personal exposures and home outdoor levels of sulfur were highly correlated (n = 40, rSp = 0.85). In contrast, the associations were weaker for traffic (Pb: n = 44, rSp = 0.53; Br: n = 44, rSp = 0.21) and crustal (Ca: n = 44, rSp = 0.12) indicators. This contrast is consistent with spatially homogeneous regional pollution and higher spatial variability of traffic and crustal indicators observed in Basel, Switzerland. We conclude that for regional air pollution, fixed-site fine particle levels are valid exposure surrogates. For source-specific exposures, however, fixed-site data are probably not the optimal measure. Still, in air pollution epidemiology, ambient PM2.5 levels may be more appropriate exposure estimates than total personal PM2.5 exposure, since the latter reflects a mixture of indoor and outdoor sources.  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