Perhaps you should try some spelling variations:
hanh trinh » canh tranh
hieu quan » hieu qua, lieu quan, thien quan
hoi hieu » hoi phieu, hoi tieu, moi hieu
cua song » cua cong, qua song, cua dong
hong tac » huong tac, cong tac, dong tac
toan cao » toan tap
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: hoi hieu quan - ((hanh trinh) or (hanh chinh)) cua song hong tac ((toan cao) or (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoi hieu quan - ((hanh trinh) OR (hanh chinh)) cua song hong tac ((toan cao) OR (toan ban)).
• Adding a wildcard symbol may retrieve word variants: hoi hieu quan - ((hanh trinh) or (hanh chinh)) cua song hong tac ((toan cao) or (toan ban))*.