Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
thanh vi » hanh vi, thanh va, thanh ve
dang xay » dang van, van xay
van cam » van nam, van lam, van cau
cua tre » cuu tre, cua triet, dua tren
duc ban » duc tan, duc van, dua ban
cam duc » cam xuc, cao duc, pham duc
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
dang xa » lang xa, dang ha, dang va
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky ((dang xa) or (dang xay)) hoi. hieu van cam duc ban thanh vi ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((dang xa) OR (dang xay)) hoi. hieu van cam duc ban thanh vi ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: su sach ky ((dang xa) or (dang xay)) hoi. hieu van cam duc ban thanh vi ((cua tre) or (cua te))*.