Keywords fetal;thymus;diffuse neuroendocrine system;chromogranin A;neuron specific enolase;somatostatin;vasoactive intestinal peptide;

• 关键词胎儿;胸腺;弥散神经内分泌系统;嗜铬素A;神经元特异性烯醇化酶;生长抑素;血管活性肠肽;