Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
so sach » so sanh, bo sach, co sach
va hanh » va thanh, va danh, ban hanh
tai cua » thai cua, tai cuc, tri cua
dai hoi » dai hoc, dai hai, dai moi
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
cac luc » cau luc, coc luc, cac nuoc
ve cac » va cac, vien cac
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky nang ((cau hoi) or (dai hoi)). hieu ve cac luc ((va hanh) or (van hanh)) tai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang ((cau hoi) OR (dai hoi)). hieu ve cac luc ((va hanh) OR (van hanh)) tai cua te.
• Adding a wildcard symbol may retrieve word variants: so sach ky nang ((cau hoi) or (dai hoi)). hieu ve cac luc ((va hanh) or (van hanh)) tai cua te*.