Perhaps you should try some spelling variations:
trong thanh » truong thanh, trung thanh, rong thanh
hanh trinh » hanh chinh
hieu quan » hieu qua, lieu quan, thien quan
hoi hieu » hoi phieu, hoi tieu, moi hieu
cua dung » cua dang, cua dong, qua dung
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 (canh tranh)) cua dung trong thanh ((toan cao) OR (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoi hieu quan - ((hanh trinh) OR (canh tranh)) cua dung trong thanh ((toan cao) OR (toan ban)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoi hieu quan - ((hanh trinh) or (canh tranh)) cua dung trong thanh ((toan cao) OR (toan ban))".
• Adding a wildcard symbol may retrieve word variants: hoi hieu quan - ((hanh trinh) or (canh tranh)) cua dung trong thanh ((toan cao) OR (toan ban))*.