fixed dam固定挡板fixedadj.固定的；不变的；确定的动词fix的过去式和过去分词.fixed letter of revenue确定收入单证fixed coordinate system固定坐标系fixed bridge prosthesis[医] 固定桥修复术fixed permanent segment固定永久段Fixed alternate routing固定备选路由fixed-focus operation定焦点操作fixed ion concentration固定离子浓度fixed-volume stopcock定体积旋塞fixed funds of commerce商业固定资金fixed - term contract固定期限劳动合同