Perhaps you should try some spelling variations:
thanh toan » thanh hoa, thanh san, tinh toan
thanh tai » thanh hai, doanh tai, thanh san
tu sach » thu sach, su sach, te sach
dua ban » dia ban, cua ban, qua ban
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
tang ma » mang may, tang van
sang ma » nang ma, sang tao, mang may
ca dua » cay dua, ca cua, ca da
va ca » va cac, va cao, va cai

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 ky ((sang ma) or (tang ma)) hoa. hieu va ca dua ban ((thanh tai) OR (thanh toan)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((sang ma) OR (tang ma)) hoa. hieu va ca dua ban ((thanh tai) OR (thanh toan)) cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((sang ma) or (tang ma)) hoa. hieu va ca dua ban ((thanh tai) OR (thanh toan)) cua tre*".