Perhaps you should try some spelling variations:
thanh toan » thanh hoa, thanh san, tinh toan
pham thuc » phap thuc, pham chuc, nham thuc
thanh va » thanh van, hanh va, thanh ha
su sach » so sach, vu sach
thuc va » thuc vat, thuc dan, thuc day
va pham » van pham, va phat, va phap
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
mai hoi » mai khoi, dai hoi, lai hoi
ty hang » ly hang, ty xang, thi hang
cua tre » cua te, cuu tre, cua triet
ma hoi » xa hoi, ma hoa, me hoi

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 ty hang ((ma hoi) or (mai hoi)). hieu va pham thuc va ((thanh va) or (thanh toan)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty hang ((ma hoi) OR (mai hoi)). hieu va pham thuc va ((thanh va) OR (thanh toan)) cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ty hang ((ma hoi) or (mai hoi)). hieu va pham thuc va ((thanh va) or (thanh toan)) cua tre*.