每半年的保养  semiannual maintenance

每半年的保养计划表  semiannual maintenance schedule

每年的保养  yearly maintenance

每半年的  half-yearly; Semiannual

需要的保养  required maintenance

需要的保养程序  required maintenance procedure

需要的保养措施  required maintenance practice

保养要求  maintenance requirement

每半年  semiannually; halfyearly

每半年地  biannually

每年的  Annual; Yearly

每年的预防保养检查  yearly preventive maintenance check

每周的保养  weekly maintenance

每周的保养检查  weekly maintenance check

半年[的]  semi-annual

年年的  year-by-year

提供一年保养  offer a one-year warranty

CT球管的保养与维护  The maintenance of CT tube

IMO和IALA的要求  requirement from IMO and IALA