Perhaps you should try some spelling variations:
hieu nganh » hiem ngan, hieu manh, nghiep nganh
vien nganh » vien thanh
thanh tran » thanh trang, thanh toan, thanh tra
tran van » luan van
van bang » van ban, van nang, von bang
cong tac » cong ty
than cao » toan cao, thai cao, than cap

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: doc ((hieu nganh) OR (vien nganh)) - thanh tran van bang ((cong san) OR (cong tac)) than cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu nganh) or (vien nganh)) - thanh tran van bang ((cong san) OR (cong tac)) than cao~".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu nganh) or (vien nganh)) - thanh tran van bang ((cong san) OR (cong tac)) than cao*.