In vitro accelerative fatigue test of expanded polytetrafluoroethylene mitral valve prothesis .
膨体聚四氟乙烯人工二尖瓣的体外加速疲劳实验。
China is in the accelerative stage of industrialization and economy and has the large demand of petroleum , while the domestic supply of petroleum is hard to upswing and can not meet the need . So we need import to sustain the development of economy .