共 6 条
[2]
DRUMM JE, 1978, RECENT ADV ULTRASOUN, P155
[3]
HAMILTON WJ, 1972, TXB HUMAN EMBRYOLOGY
[5]
DETECTION OF FETAL HEART MOVEMENT IN FIRST TRIMESTER OF PREGNANCY USING PULSED ULTRASOUND
[J].
BMJ-BRITISH MEDICAL JOURNAL,
1972, 4 (5838)
:466-+
[6]
TIMMONS DJ, 1963, AM J OBSTET GYNECOL, V86, P875