Perhaps you should try some spelling variations:
xuyen tai » xuyen tac, 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 khu » cac thu, cac kieu
ban ly » ban lay, bang ly, ban le
ky thu » ly thu, ky thi, ky thuat
ly ky » ly y

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

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