For over a century, the embryologists had been pondering the mysteries of heart development.

一个多世纪以来，胚胎学家一直在思考心脏发育的奥秘。

Certain immune and pathological aspects of HIV infection are closely related to problems faced by obstetricians, embryologists, gynecologists , and andrologists.

HIV感染的某些免疫学与病理学方面与产科医师、胚胎学家、妇科医师以及男科学家所面临的问题紧密相关。