Perhaps you should try some spelling variations:
thanh trung » thanh tung
chiet tach » chieu sach
nhung dong » nhung don, nhung cong, nhung dung
hieu cach » hieu cac, chieu sach, hieu ca
trung cua » truong cua, trung tuan, trung cap
cua nhung » va nhung
dong bang » dong san
bang than » bang thanh, ban than, sang than
than cau » toan cau, phan cau, than cap

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((hieu cach) or (chiet tach)) - thanh trung cua nhung dong bang than cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu cach) OR (chiet tach)) - thanh trung cua nhung dong bang than cau.
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu cach) or (chiet tach)) - thanh trung cua nhung dong bang than cau*.