Perhaps you should try some spelling variations:
chiet tach » chieu sach
nhung cong » dung cong, thong cong, hang cong
trinh va » trinh van, trinh vat, trinh vi
trinh ve » trinh he, trinh vi, trinh viet
cong san » cong tac
san toan » van toan, dan toan, manh toan
toan tap » toan 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: ho ((chiet tach) OR (chinh sach)) - hanh ((trinh va) OR (trinh ve)) nhung cong san toan tap~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((chiet tach) or (chinh sach)) - hanh ((trinh va) OR (trinh ve)) nhung cong san toan tap~".
• Adding a wildcard symbol may retrieve word variants: ho ((chiet tach) or (chinh sach)) - hanh ((trinh va) OR (trinh ve)) nhung cong san toan tap*.