He completed a one-year clerkship as a doctor's assistant during his hospital training.

clerkship 是由名词 clerk（职员、办事员）加上后缀 -ship 构成的名词。clerk 指从事文书或行政工作的人员，-ship 表示"身份、职位或关系"。 clerkship 在这里特指"医生助理的实习职位"，是医学生在医院培训期间担任的初级医疗岗位，协助医生工作并积累临床经验。