Perhaps you should try some spelling variations:
nghe thuoc » nghe thuc, nghiem thuoc, nghe thuat
thuoc hoc » thuoc ho, thuoc nhom, thuong hoc
thu sach » tu sach, thuat sach, thuoc sach
kho nghe » so nghe, o nghe
bai nghe » thai nghe, van nghe, nam nghe
su cac » tu cac, su cao, eu cac
tu hoc » te hoc
su can » su van, su cao, tu can

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( ((su cac) or (su can)) bai nghe thuoc hoc ) or ( thu sach ((khoe nghe) or (kho nghe)) tu hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( ((su cac) OR (su can)) bai nghe thuoc hoc ) OR ( thu sach ((khoe nghe) OR (kho nghe)) tu hoc )).
• Adding a wildcard symbol may retrieve word variants: (( ((su cac) or (su can)) bai nghe thuoc hoc ) or ( thu sach ((khoe nghe) or (kho nghe)) tu hoc ))*.