Perhaps you should try some spelling variations:
cong thanh » dong thanh, cong trinh, truong thanh
ho chieu » theo chieu, hoc thieu, doi chieu
tinh tan » tinh toan, tinh than, trinh tan
van nang » van quang, van ban, van dong
cong tan » cong tac, cong san, cong ty
toan cao » toan ban, toan tap
tan van » tran van, tang van, luan van

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 chieu) OR (theo tieu)) xanh - tinh tan van nang ((cong tan) OR (cong thanh)) toan cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho chieu) or (theo tieu)) xanh - tinh tan van nang ((cong tan) OR (cong thanh)) toan cao~".
• Adding a wildcard symbol may retrieve word variants: ((ho chieu) or (theo tieu)) xanh - tinh tan van nang ((cong tan) OR (cong thanh)) toan cao*.