421例早中期妊娠孕妇血清中维生素D及微量元素水平分析
张文文,汪之顼
Levels of serum vitamin D and trace elements in 421 pregnant women in early and middle trimester of pregnancy
ZHANG Wen-wen, WANG Zhi-xu
中国校医 . 2020, (3): 170 -171,240 .