差频与差拍
何谓功能性胃肠病及其主要表现?
食管癌水平照射野的后界要压在椎体前缘的() ["A．1/3～1/2处","B．1/2～2/3处","C．1/3～1/4处","D．1/4～1/5处","E．1/5～1/6处"]
食管癌一前两后野定位，机架应为() ["A．-10°、-140°、+120°","B．0°、-130°、+130°","C．10°、-120°、+140°","D．0°、-120°、+120°","E．10°、-130°、+130°"]
寄生离子
简述胃泌素的作用及其调控因素。
