Studies of energy spectrum analysis on the absorption and distributive laws of nutrient elements in sucking roots of ginkgo biloba l.

银杏吸收根营养元素吸收及分配规律的能谱分析。

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Based on the regional distributive laws of natural hazards and economics in Hebei province, the principles, methods and index systems of Hebei natural hazard regionalization have been advanced.

根据河北省自然灾害的区域分异规律和社会经济状况，提出了河北省自然灾害区划的原则、方法指标体系，进行了自然灾害区划，并对不同灾害区提出了防灾减灾对。

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