Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
cao duc » dao duc, cao suc, giao duc
va danh » va dinh, va dan, va hanh
danh va » doanh va, hanh va, anh va
su tien » su kien, su hien, tu tieng
ve cao » va cao, ve bao, ve cac

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 y ((mang may) or (nang x)) hoi. hieu ve cao duc va danh va su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((mang may) OR (nang x)) hoi. hieu ve cao duc va danh va su tien.
• Adding a wildcard symbol may retrieve word variants: tu sach y ((mang may) or (nang x)) hoi. hieu ve cao duc va danh va su tien*.