期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
简论省级电大校报辐射指向趋势——以《陕西电大报》为例
1
作者 月人 《陕西广播电视大学学报》 2010年第3期83-84,共2页
大学校报的发行对象即辐射指向,大致可分为对内对外两大类。对内又可分为学生、教师、干部三类对象;对外也可分为上级教育行政机构、兄弟院校与科研院所、社会媒体机构三类对象。
关键词 省级电大校报 电大报辐射 辐射指向 指向趋势
下载PDF
Spatial and environmental effects on plant communities in the Yellow River Delta, Eastern China 被引量:8
2
作者 宋创业 刘高焕 刘庆生 《Journal of Forestry Research》 SCIE CAS CSCD 2009年第2期117-122,I0002,共7页
Types and structure of plant communities in the Yellow River Delta were investigated by using detrended canonical correspondence analyses (DCCAs) and a two-way indicator species analysis (TWINSPAN). The distributi... Types and structure of plant communities in the Yellow River Delta were investigated by using detrended canonical correspondence analyses (DCCAs) and a two-way indicator species analysis (TWINSPAN). The distribution pattern and influential factors of the plant communities were also analyzed by testing elevation, slope, soil characteristics, longitude and latitude of 134 vegetation samples collected by representative plot sampling methods. Results showed that all the 134 vegetation samples could be divided into seven vegetation groups, separately dominated by Robinia pseucdoacacia, Imperata cylindrical, Miscanthus saccharifleus, Suaeda salsa, Aeluropus sinensis, Phragmites australis and Tamarix chinensis. The vegetation distribution pattern was mainly related to elevation, ground water depth and soil characteristics such as salinity and soluble potassium. Among the factors affecting distribution pattern of the plant communities, the species matrix explained by non-spatial environmental variation accounts for 45.2% of total variation. Spatial variation and spatial-structured environmental variation explain 11.8%, and 2.2%, respectively. Remained 40.8% of undetermined variation is attributed to biological and stochastic factors. 展开更多
关键词 detrended canonical correspondence analyses environmental factors plant communities spatial factors Yellow River Delta two-way indicator species analysis
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部