短語詞組短語secular gravity variation 長期性重力變化secular variation trend 長期變化趨勢geomagnetic secular variation [地物]地磁長期變化the secular variation 變化特點secular variation features 長期變化特征paleomagnetic secular variation 古地磁場長期變化secular variation detail 長年變化magnetic recording wire secular variation 地磁長期變化secular variation of geomagnetic field 地磁場長期變化 返回 secular variation