卵黄囊
yolk sac (ectodermal cells attaching fetus to uterus before the development of the placenta)
词频 2.4
含义
- yolk sac (ectodermal cells attaching fetus to uterus before the development of the placenta)
yolk sac (ectodermal cells attaching fetus to uterus before the development of the placenta)
词频 2.4