基本解釋[經(jīng)濟(jì)學(xué)]可變膨脹偏心凸輪詞組短語短語variable e expansion eccentric cam 可變膨脹偏心凸輪variable expansion eccentric cam更多詞組專業(yè)釋義經(jīng)濟(jì)學(xué)可變膨脹偏心凸輪