Perhaps you should try some spelling variations:
thanh toan » thanh hoa, thanh san, tinh toan
thanh van » thanh san, thanh phan, thanh nhan
hieu van » hieu va, thien van, lieu va
lam duc » lam duoc, pham duc, nam duoc
duc ban » duc tan, duc van, dua ban
su sach » so sach, vu sach
van lam » van nam
sach ky » sac ky, sach y, sach ty
lang ha » long ha
lang xa » dang xay, lang van
cua tre » cua te, cuu tre, cua triet

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 ((lang xa) or (lang ha)) hoi. hieu van lam duc ban ((thanh van) OR (thanh toan)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((lang xa) OR (lang ha)) hoi. hieu van lam duc ban ((thanh van) OR (thanh toan)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((lang xa) or (lang ha)) hoi. hieu van lam duc ban ((thanh van) OR (thanh toan)) cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((lang xa) or (lang ha)) hoi. hieu van lam duc ban ((thanh van) OR (thanh toan)) cua tre*.