McGregor JA, Leff M, Orleans M, Baron A. Fetal gender differences in preterm birth: findings in a North American cohort. Am J Perinatol 1992;9:43-8.是什么意思_McGregor JA, Leff M, Orleans M, Baron A. Fetal gender differences in preterm birth: findings in a North American cohort. Am J Perinatol 1992;9:43-8.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句