Perhaps you should try some spelling variations:
thanh trung » thanh tung
thien thanh » tien thanh, thi thanh, hien hanh
cong thanh » dong thanh, cong trinh, truong thanh
tien manh » tien anh, tien thanh, tieng anh
trung va » truong va, trang va, trung ha
cong tan » cong tac, cong san, cong ty
toan cao » toan ban, toan tap
va dung » van dung, va duong, vat dung

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

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