Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sach » chinh sach, chieu sang, chieu xanh
nhung cong » dung cong, thong cong, hang cong
manh tung » manh hung, thanh tung
cong tac » cong ty
tac toan » tap toan, tam toan, hach toan
toan ban » van ban

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: doi ((chieu sach) OR (chiet tach)) - ((thanh trung) OR (manh tung)) va nhung cong tac toan ban~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi ((chieu sach) OR (chiet tach)) - ((thanh trung) or (manh tung)) va nhung cong tac toan ban~".
• Adding a wildcard symbol may retrieve word variants: doi ((chieu sach) OR (chiet tach)) - ((thanh trung) or (manh tung)) va nhung cong tac toan ban*.