Perhaps you should try some spelling variations:
phuong van » phung van, phuong lan, phuong va
hieu lang » chieu sang, hieu quang, nhieu tang
tuan doan » quan doan, tuan hoan, tran doan
phong van » phung van, thong van, phong va
doi hieu » doi chieu, doc hieu, doi hien
tan doan » tran doan, tap doan, van doan
ban tai » van tai, han tai, ban thi

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi hieu lang - canh tranh ((tuan doan) OR (tan doan)) ((phuong van) or (phong van)) ban tai~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi hieu lang - canh tranh ((tuan doan) OR (tan doan)) ((phuong van) OR (phong van)) ban tai.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi hieu lang - canh tranh ((tuan doan) OR (tan doan)) ((phuong van) or (phong van)) ban tai".
• Adding a wildcard symbol may retrieve word variants: doi hieu lang - canh tranh ((tuan doan) OR (tan doan)) ((phuong van) or (phong van)) ban tai*.