Perhaps you should try some spelling variations:
quyen tai » xuyen tai, nguyen tai, truyen tai
cong cong » cong dong, trong cong, dang cong
dung cong » dung trong
cac khoi » cac thoi, cac khoan, cach thoi
cac thu » cach thuc, cac thoi
cac khu » cac kieu
ban ke » ban kem, ban ve, ban le
ke y » ke ky, ke o

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

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