短語詞組短語backward d integration 逆向合并backward Euler integration 隱式Euler方法Backward vertical integration 向后垂直整合;整合;后向一體化backward forward integration 前后向合并backward Euler integration method 后向歐拉積分法vertical backward integration 后向合并B backward integration 后向歸并backward integration algorithm 后向積分法backward integration techniques 反向積分技術(shù) 返回 backward integration