Perhaps you should try some spelling variations:
canh nganh » canh tranh, cac nganh, canh ngon
dung cong » dung trong
hoc hieu » hoc thieu, hoc hien, doc hieu
mac dung » tac dung, mai dung, mac dong
dan than » dan chan, ban than, van than
hieu ca » hieu cac, hieu cua, hieu va
van tan » van tuan, van ban, van tai

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 ca - canh nganh mac dung cong ((van tan) or (dan than)) tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu ca - canh nganh mac dung cong ((van tan) OR (dan than)) tap*.