Perhaps you should try some spelling variations:
thanh trung » thanh tung
hieu manh » chieu xanh, hieu nganh, hien hanh
hang cong » dang cong, hang nong, bang cong
trung va » truong va, trang va, trung ha
cong dan » cong san, cong tan, huong dan
toan cao » toan tap
toan ban » van ban
va hang » van hang, va nang, va lang

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: hoc ((hieu manh) OR (dieu hanh)) - thanh trung va hang cong dan ((toan cao) OR (toan ban))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu manh) or (dieu hanh)) - thanh trung va hang cong dan ((toan cao) OR (toan ban))~".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu manh) or (dieu hanh)) - thanh trung va hang cong dan ((toan cao) OR (toan ban))*.