Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh hai » thanh phan, thanh hoa, thanh san
cua triet » cua viet, su triet, va triet
nang xa » lang xa, nang ma, mang xa
duc ban » duc tan, duc van, dua ban
cua tre » cua te, cuu tre, dua tren
su xac » pu xac, su cac
xac ky » cac ky, sac ky, bac ky
hieu v » hieu va, hieu ve, hieu 2
v pham » vi pham, d pham

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

• Performing a fuzzy search may retrieve terms with similar spellings: su xac ky ((nang xa) or (nang x)) hoi. hieu v pham duc ban thanh hai ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su xac ky ((nang xa) OR (nang x)) hoi. hieu v pham duc ban thanh hai ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su xac ky ((nang xa) or (nang x)) hoi. hieu v pham duc ban thanh hai ((cua tre) OR (cua triet))".
• Adding a wildcard symbol may retrieve word variants: su xac ky ((nang xa) or (nang x)) hoi. hieu v pham duc ban thanh hai ((cua tre) OR (cua triet))*.