Perhaps you should try some spelling variations:
nghe thuoc » nghe thuc, nghiem thuoc, nghe thuat
thuoc hoc » thuoc ho, thuoc nhom, thuong hoc
khoe nghe » kho nghe
chon nghe » cuong nghe, cong nghe, kho nghe
nam nghe » nang nghe, van nghe
tu sach » thu sach, su sach, te sach
su cao » cu cao, vu cao, su co
su can » su van, tu can, su han

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

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