Perhaps you should try some spelling variations:
thieu nghe » thieu nhi, lieu nghe, nhiem nghe
nhung don » nhung van
hoc thieu » toc thieu, hoc hien
nghe cua » nghiep cua, nghe va, nghe che
khoa hoc » hoa hoc
nhung bo » nhung bi, nhung bai, trung bo
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
co gio » co giao, co gioi, co gi

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) OR (su sach)) khoa hoc thieu nghe cua ets : ((nhung bo) or (nhung don)) co gio đai~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) khoa hoc thieu nghe cua ets : ((nhung bo) OR (nhung don)) co gio đai.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) khoa hoc thieu nghe cua ets : ((nhung bo) or (nhung don)) co gio đai".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (su sach)) khoa hoc thieu nghe cua ets : ((nhung bo) or (nhung don)) co gio đai*.