Perhaps you should try some spelling variations:
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu va, hieu van
can cau » van cau, ban cau, ca cau
cac tuc » cac toc, cac tu, cac tac
cac cau » cac mau, bac cau, ca cau
ca dan » cac dan, ca dao
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
va dan » va dao, va dau, va dap
ve cac » va cac, vien 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 sac ky nang cao hoi. hieu ve cac tuc ((va dan) OR (ca dan)) ((cac cau) or (can cau)) tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky nang cao hoi. hieu ve cac tuc ((va dan) OR (ca dan)) ((cac cau) OR (can cau)) tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky nang cao hoi. hieu ve cac tuc ((va dan) OR (ca dan)) ((cac cau) or (can cau)) tren".
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang cao hoi. hieu ve cac tuc ((va dan) OR (ca dan)) ((cac cau) or (can cau)) tren*.