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   1168篇
  免费   12篇
  国内免费   1篇
安全科学   24篇
废物处理   74篇
环保管理   75篇
综合类   207篇
基础理论   195篇
污染及防治   401篇
评价与监测   117篇
社会与环境   81篇
灾害及防治   7篇
  2023年   14篇
  2022年   39篇
  2021年   45篇
  2020年   20篇
  2019年   22篇
  2018年   67篇
  2017年   35篇
  2016年   69篇
  2015年   55篇
  2014年   64篇
  2013年   91篇
  2012年   52篇
  2011年   85篇
  2010年   71篇
  2009年   38篇
  2008年   74篇
  2007年   67篇
  2006年   55篇
  2005年   42篇
  2004年   31篇
  2003年   31篇
  2002年   24篇
  2001年   19篇
  2000年   12篇
  1999年   7篇
  1998年   2篇
  1997年   1篇
  1996年   6篇
  1995年   5篇
  1994年   8篇
  1993年   5篇
  1992年   4篇
  1990年   3篇
  1989年   1篇
  1988年   1篇
  1986年   1篇
  1985年   2篇
  1984年   2篇
  1983年   1篇
  1982年   2篇
  1981年   2篇
  1979年   2篇
  1978年   1篇
  1975年   1篇
  1964年   1篇
  1962年   1篇
排序方式: 共有1181条查询结果,搜索用时 15 毫秒
961.
962.
963.
964.
965.
966.
Environmental Science and Pollution Research - This study evaluates the elemental (W, Mo, Zn, Fe, Cu, Cd, Mn, Pb, Cr, Co, B, and Bi) composition of Marrubium astracanicum Jacq. (Lamiaceae), around...  相似文献   
967.
968.
In International Union for Conservation of Nature (IUCN) Red List assessments, extent of occurrence (EOO) is a key measure of extinction risk. However, the way assessors estimate EOO from maps of species’ distributions is inconsistent among assessments of different species and among major taxonomic groups. Assessors often estimate EOO from the area of mapped distribution, but these maps often exclude areas that are not habitat in idiosyncratic ways and are not created at the same spatial resolutions. We assessed the impact on extinction risk categories of applying different methods (minimum convex polygon, alpha hull) for estimating EOO for 21,763 species of mammals, birds, and amphibians. Overall, the percentage of threatened species requiring down listing to a lower category of threat (taking into account other Red List criteria under which they qualified) spanned 11–13% for all species combined (14–15% for mammals, 7–8% for birds, and 12–15% for amphibians). These down listings resulted from larger estimates of EOO and depended on the EOO calculation method. Using birds as an example, we found that 14% of threatened and near threatened species could require down listing based on the minimum convex polygon (MCP) approach, an approach that is now recommended by IUCN. Other metrics (such as alpha hull) had marginally smaller impacts. Our results suggest that uniformly applying the MCP approach may lead to a one‐time down listing of hundreds of species but ultimately ensure consistency across assessments and realign the calculation of EOO with the theoretical basis on which the metric was founded.  相似文献   
969.
Objectives. The purpose of this study is to evaluate the influence of the work surface and task difficulty on the head, upper back and upper arm postures and activity of the descending trapezius during a simulated mouse task. Methods. Healthy female university students (N?=?15) were evaluated. The work surface was positioned at elbow height (EH) and above elbow height (AEH) and the task difficulty was set at low (LD) and high (HD) levels. The postures were recorded by inclinometers. Trapezius activity was normalized by the maximum voluntary isometric contraction (MVIC). Results. Significantly higher head flexion was found at EH compared to the AEH condition, with an average difference of 2°–5° at the same difficulty level. The HD task significantly increased head (3°–6°) and upper back flexion (6°–7°) at the same table height. For upper arm elevation and trapezius activation, the AEH condition presented higher upper arm elevation (about 6°–8°) and trapezius activity (0.8–1.4% of MVIC), regardless of the difficulty level of the task. Conclusions. Head posture was influenced by the table height and task difficulty; the upper back posture by high difficulty; and upper arm posture and trapezius activity were only influenced by table height.  相似文献   
970.
We report relatively high trehalase activity in amniotic fluid of a fetus affected with the autosomal recessive type of polycystic kidney disease (type II), suggesting that prenatal detection of this condition could be done on this basis in conjunction with ultrasonography.  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