Perhaps you should try some spelling variations:
thanh trung » thanh tung
thiet tach » chiet tach, thien hach, thuat tach
hoc thiet » hoc thieu, hoc thuyet, hoc hien
trung cua » truong cua, trung tuan, trung cap
cong toan » cong tan, cong tuan, cong doan
cong hoan » cong hoa, dong hoa, cong san
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.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc thiet tach - thanh trung cua tong ((cong toan) or (cong hoan)) phan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thiet tach - thanh trung cua tong ((cong toan) OR (cong hoan)) phan cau.
• Adding a wildcard symbol may retrieve word variants: hoc thiet tach - thanh trung cua tong ((cong toan) or (cong hoan)) phan cau*.