国内外研究人员通常采用主成分分析法、熵值法、灰色关联法、多层次模糊评价等方法对煤层气开发甜点区进行评价 ...
DAR ES SALAAM, Jan. 24 (Xinhua) -- Tanzania has begun implementing a nationwide program to establish district-level industrial parks and clusters to add value to products from agriculture, livestock, ...
Northwestern Chinese regions like Qinghai, Xinjiang and Ningxia have turned their sunbaked, wind-swept deserts into treasure ...
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