Perhaps you should try some spelling variations:
trong dang » truong dang, trong dan, trong dung
trong dong » trong cong, trong nong, trong dung
hieu tinh » chieu tinh, lieu tinh, kieu tinh
thanh cac » hanh cac, thanh bac, thanh ca
doc hieu » toc thieu, hoc thieu, hoc hien
cua dung » cua dang, qua dung, cua rung
cua dong » chua dong, cua cong, cua dang

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu tinh - canh tranh ((cua dung) or (cua dong)) ((trong dang) or (trong dong)) thanh cac~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu tinh - canh tranh ((cua dung) OR (cua dong)) ((trong dang) OR (trong dong)) thanh cac.
• Adding a wildcard symbol may retrieve word variants: doc hieu tinh - canh tranh ((cua dung) or (cua dong)) ((trong dang) or (trong dong)) thanh cac*.