Perhaps you should try some spelling variations:
quyen tap » tuyen tap, luyen tap, quyen cap
cac khoi » cac khoan, cach thoi, hoc khoi
cac thoi » cac toi, cac hop, cac tro
thi cong » tai cong, thien cong
cac chu » cac thu, cac che, cac khu
te cong » tai cong, thu cong
ban ve » ban va
ve y » ve ky, ve _, ke y

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 chu) or (((cac khoi) or (cac thoi)))) đe co ban ve y ((te cong) OR (thi cong)) cong~.
• If you are trying to use Boolean operators, they must be ALL CAPS: quyen tap ((cac chu) OR (((cac khoi) OR (cac thoi)))) đe co ban ve y ((te cong) OR (thi cong)) cong.
• The words AND, OR and NOT may confuse the search; try adding quotes: "quyen tap ((cac chu) or (((cac khoi) or (cac thoi)))) đe co ban ve y ((te cong) OR (thi cong)) cong".
• Adding a wildcard symbol may retrieve word variants: quyen tap ((cac chu) or (((cac khoi) or (cac thoi)))) đe co ban ve y ((te cong) OR (thi cong)) cong*.