Perhaps you should try some spelling variations:
thanh trung » thanh tung
hieu tach » hieu cach, chiet tach, chieu sach
hanh tang » hanh trang, anh tang, hanh mang
doc hieu » toc thieu, hoc thieu, hoc hien
cong tan » cong san, cong thanh, cong ty
cong tac » cong ty
tran cao » toan cao, tran chau, trang cho

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu tach - ((hanh tang) or (thanh trung)) va nhung ((cong tan) OR (cong tac)) tran cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu tach - ((hanh tang) OR (thanh trung)) va nhung ((cong tan) OR (cong tac)) tran cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu tach - ((hanh tang) or (thanh trung)) va nhung ((cong tan) OR (cong tac)) tran cao".
• Adding a wildcard symbol may retrieve word variants: doc hieu tach - ((hanh tang) or (thanh trung)) va nhung ((cong tan) OR (cong tac)) tran cao*.