短语词组短语chain vector -length 链矢量长度chain -length-factor 链Medium -chain-length polyhydroxyalkanoate 中长链聚羟基脂肪酸酯medium -chain-length-PHAs 中长链羟基脂肪酸聚酯short -chain-length-PHAs 比短链羟基脂肪酸聚酯double -chain length 双链长度 返回 chain length