共 48 条
[2]
[Anonymous], 2008, FERTIL STERIL S3, V90, pS163
[3]
[Anonymous], 1996 ASS REPR TECHN
[4]
[Anonymous], 2010, National Vital Statistics Reports, V61, P1
[5]
[Anonymous], 2009, FERTIL STERIL, V92, P1518
[6]
[Anonymous], 2006, PRETERM BIRTH CAUSES
[7]
[Anonymous], 2003, MMWR, V52
[8]
[Anonymous], 2004, FERTIL STERIL S1, V82, P1