Perhaps you should try some spelling variations:
thanh trung » thanh tung
thieu tach » chiet tach, chieu sach, hieu cach
thien hach » thien thanh, hien hanh
tong huong » thong huong, tong thuong, cong huong
trung cua » truong cua, trung tuan, trung cap
cua tong » cua cong, cua dong, cua nong
phan cau » phan dau, phan cac, phan tu

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 ((thieu tach) OR (thien hach)) - thanh trung cua tong huong dan ((phan cau) OR (hang va))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu tach) OR (thien hach)) - thanh trung cua tong huong dan ((phan cau) or (hang va))~".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu tach) OR (thien hach)) - thanh trung cua tong huong dan ((phan cau) or (hang va))*.