基于物元可拓法的地下水水质评价&以梨树县平原区浅层地下水为例
Evaluation of Groundwater Quality Based on Matter-Element and Extension Means-Taking Shallow Groundwater of Plain Areas in Lishu for Example
青海的梨树资源集中分布区在贵德、乐都、民和三县。
The resources of pear trees is distributed mainly in Guide county 、 Ledu county and Minhe county .