Perhaps you should try some spelling variations:
thiet thanh » thi thanh, viet thanh, them thanh
thien thanh » tien thanh, thi thanh, hien hanh
thanh trung » thanh tung
cua thuong » cua truong, cua phuong, ca thuong
trung cua » truong cua, trung tuan, trung cap
cong tan » cong tac, cong thanh, cong ty
cong san » cong tac
phan cau » phan dau, phan cac, phan tu

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

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