Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
trinh quan » tinh quang, trinh luat, trinh han
hieu quan » hieu qua, lieu quan, thien quan
hoi hieu » hoi phieu, hoi tieu, moi hieu
hong tac » huong tac, cong tac, dong tac
tac toan » tap toan, tam toan, hach toan
toan cao » toan ban, toan tap

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 quan (song or dong) hong tac toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoi hieu quan - hanh trinh quan (song OR dong) hong tac toan cao.
• Adding a wildcard symbol may retrieve word variants: hoi hieu quan - hanh trinh quan (song or dong) hong tac toan cao*.