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

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