Perhaps you should try some spelling variations:
thanh toan » thanh hoa, thanh san, tinh toan
thanh tai » thanh hai, doanh tai, thanh san
tang van » dang van, hoang van, trong van
tu sach » thu sach, su sach, te sach
duc ban » duc tan, duc van, dua ban
cam duc » cam xuc, cao duc, pham duc
sach tu » sach thu, cach tu, sach ty
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach tu ((tang van) or (lang xa)) hoi. hieu va cam duc ban ((thanh tai) OR (thanh toan)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tu ((tang van) OR (lang xa)) hoi. hieu va cam duc ban ((thanh tai) OR (thanh toan)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach tu ((tang van) or (lang xa)) hoi. hieu va cam duc ban ((thanh tai) OR (thanh toan)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach tu ((tang van) or (lang xa)) hoi. hieu va cam duc ban ((thanh tai) OR (thanh toan)) cua tre*.