短语词组短语diamond core drill bit 金刚石钻头two core per bit 每位两个磁心core -bit tap 打捞金刚石取心钻头的公锥core drilling bit 取心钻头diamond core boring bit 金刚石空心钻头;金刚石套料钻core drill bit 岩芯钻头core cone bit 牙轮取心钻头Core Box Bit 圆底刀 返回 core bit