Perhaps you should try some spelling variations:
quyen tap » tuyen tap, luyen tap, quyen cap
cong cong » cong dong, trong cong, dang cong
dung cong » dung trong
cac khu » cac khoi, cac kieu
va kiem » van kien
cac thu » cach thuc, cac thoi
ban ve » ban va
ve ky » va ky, ke ky
ky la » ky le, ky va

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

• Performing a fuzzy search may retrieve terms with similar spellings: quyen tap ((cac thu) or (((cac khu) or (va kiem)))) đe co ban ve ky la ((cong cong) OR (dung cong))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: quyen tap ((cac thu) OR (((cac khu) OR (va kiem)))) đe co ban ve ky la ((cong cong) OR (dung cong)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "quyen tap ((cac thu) or (((cac khu) or (va kiem)))) đe co ban ve ky la ((cong cong) OR (dung cong))".
• Adding a wildcard symbol may retrieve word variants: quyen tap ((cac thu) or (((cac khu) or (va kiem)))) đe co ban ve ky la ((cong cong) OR (dung cong))*.