Perhaps you should try some spelling variations:
hanh tranh » canh tranh, hanh trinh, hanh trang
hieu lang » chieu sang, hieu quang, nhieu tang
tranh cua » doanh cua, manh cua
dung cong » dung trong
hoc hieu » hoc thieu, hoc hien, doc hieu
cua dung » cua dang, cua dong, qua dung
dan toan » dan than, manh toan, xuan toan
van toan » van tuan, van tan, van thanh

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 lang - hanh tranh cua dung cong ((dan toan) or (van toan)) ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - hanh tranh cua dung cong ((dan toan) OR (van toan)) ban.
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - hanh tranh cua dung cong ((dan toan) or (van toan)) ban*.