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   63篇
  免费   0篇
废物处理   1篇
环保管理   9篇
综合类   30篇
基础理论   10篇
污染及防治   12篇
评价与监测   1篇
  2023年   1篇
  2019年   1篇
  2018年   1篇
  2017年   1篇
  2013年   6篇
  2012年   3篇
  2011年   1篇
  2010年   4篇
  2009年   1篇
  2008年   1篇
  2007年   2篇
  2006年   2篇
  2005年   1篇
  2004年   1篇
  2003年   2篇
  2002年   3篇
  2001年   1篇
  1996年   1篇
  1995年   4篇
  1993年   1篇
  1992年   1篇
  1990年   1篇
  1981年   1篇
  1978年   1篇
  1974年   1篇
  1972年   1篇
  1968年   2篇
  1967年   1篇
  1966年   1篇
  1964年   1篇
  1963年   1篇
  1962年   4篇
  1961年   2篇
  1960年   1篇
  1958年   1篇
  1955年   1篇
  1954年   1篇
  1942年   1篇
  1941年   1篇
  1923年   1篇
排序方式: 共有63条查询结果,搜索用时 15 毫秒
41.
42.
43.
The incidental acquisition of spatial orientation knowledge when using a pedestrian navigation assistance system for wayfinding was compared to incidental learning during map-based wayfinding. First-time visitors to a real environment (a zoo) took a guided tour. In the navigation assistance conditions, users were provided with direction information and view-based pictures of the current intersection at each decision point, presented on a hand-held computer. In the map-based condition, participants derived route segments from a map (each segment comprising three or four intersections), and then walked the partial routes from memory. After walking, unexpected tests on route memory and survey knowledge were administered. Navigation assistance users showed good route knowledge and poor survey knowledge. In contrast, map users showed better survey knowledge and nearly perfect route knowledge. Variations of information presentation within navigation assistance conditions (auditory vs. visual direction command, additional presentation of allocentric spatial information) was not effective. Results are explained with an active encoding principle. Only information that is actually encoded, transformed, and/or memorized during the primary wayfinding activity, is incidentally learned. Since navigation assistance systems do not require users to encode, transform, and memorize spatial information, the spatial orientation knowledge of navigation assistance users is poor.  相似文献   
44.
45.
46.
Intrauterine fetal brain death is a rare cause of a fixed fetal heart rate pattern. Seven cases have been previously reported in the literature, but only two of them were diagnosed prenatally and all the newborns died soon after delivery. Two additional cases of antepartum diagnosis of intrauterine fetal brain death, managed expectantly, are reported. We had the unique opportunity to document progressive sonographic cerebral changes during the follow-up period, following the neurological event, while the fetus continued life and growth in utero. The cardiographic and sonographic findings suggesting intrauterine fetal brain death were a prolonged fixed fetal heart rate, even following a vibroacoustic and contraction stress test; an atonic fetus without breathing and body movement; and the appearance of hydramnios and the development of ventriculomegaly.  相似文献   
47.
48.
49.
50.
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