Perhaps you should try some spelling variations:
thanh toan » thanh hoa, thanh san, tinh toan
tang van » dang van, hoang van, trong van
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
so sach » so sanh, bo sach, co sach
van cau » van dau, van hau, van chat
truc va » thuc va, thuc vat, trung va
cua tre » cua te, cuu tre, cua triet
y tang » ky tang, 6 tang, 7 tang

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y tang van hoa. hieu van cau truc va thanh toan ((cua tre) or (cua vat))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y tang van hoa. hieu van cau truc va thanh toan ((cua tre) OR (cua vat)).
• Adding a wildcard symbol may retrieve word variants: so sach y tang van hoa. hieu van cau truc va thanh toan ((cua tre) or (cua vat))*.