Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
bang duong » bang suong, bang tuong, tang duong
duong manh » duong van
hieu quan » lieu quan, thien quan, lien quan
luat bang » luat ban, luat bong, luat quang
manh toan » thanh toan, anh tuan, tinh toan
toan ban » van ban

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 quan) or (hieu qua)) - canh trinh luat bang duong manh toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu quan) OR (hieu qua)) - canh trinh luat bang duong manh toan ban.
• Adding a wildcard symbol may retrieve word variants: doc ((hieu quan) or (hieu qua)) - canh trinh luat bang duong manh toan ban*.