The Palaeozoic petroleum geological condition of Huabei area had been analyzed in detail from the petroliferous system angle.
从油气系统角度分析了华北区古生界的石油地质条件。
The production effects and action mechanism of applied EM biological-organic fertilizer to winter-wheat and summer-maize under the typical cropping systems of the Huabei area in china were analyzed.
本实验是在十年研究的基础上，在华北地区小麦—玉米典型耕作制度下，对土壤长期施用EM生物有机肥，研究其对冬小麦和夏玉米的生产效果与作用机理。
Tangshan city is the typical karst-cranny developing area in Huabei region which is shallowly covered up.
唐山市是华北地区典型的岩溶裂隙发育浅埋地区。
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