Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
va trien » va truyen, va thiet, va tuyen
va triet » va thiet, ve triet, cua triet
thanh vi » hanh vi, thanh va, thanh ve
pham duy » pham duc
hieu voi » hieu moi, lieu voi, hieu loi
voi pham » vi pham, toi pham, loai pham
sang tai » hang tai, sang tao, tang tai
tai hoi » tai khoi, dai hoi, tai hai
ky sang » ky nang, ky dang, ky tang
duy ban » uy ban, duy van, duy can
bo sach » co sach, hoc sach
tu cach » tu cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu cach) or (bo sach)) ky sang tai hoi. hieu voi pham duy ban thanh vi ((va triet) or (va trien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cach) OR (bo sach)) ky sang tai hoi. hieu voi pham duy ban thanh vi ((va triet) OR (va trien)).
• Adding a wildcard symbol may retrieve word variants: ((tu cach) or (bo sach)) ky sang tai hoi. hieu voi pham duy ban thanh vi ((va triet) or (va trien))*.