Perhaps you should try some spelling variations:
trung cong » truong cong, trong cong, trung uong
dau tieng » dau tien, cau tieng, mau tieng
xuyen tac » xuyen tai, nguyen tac, thuyen tac
day tieng » va tieng, ban tieng, dau tien
cac kieu » cach tieu, cac yeu, tac kiem
cac thoi » cac toi, cac hop, cac tro
ban ve » ban va

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 tac ((cac kieu) OR (cac thoi)) đe co ban ve ((dau tieng) OR (day tieng)) trung cong~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "xuyen tac ((cac kieu) or (cac thoi)) đe co ban ve ((dau tieng) OR (day tieng)) trung cong~".
• Adding a wildcard symbol may retrieve word variants: xuyen tac ((cac kieu) or (cac thoi)) đe co ban ve ((dau tieng) OR (day tieng)) trung cong*.