Perhaps you should try some spelling variations:
thanh toan » thanh hoa, thanh san, tinh toan
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
toan cua » than cua, tan cua, doanh cua
sach ky » sac ky, sach y, sach kem
cua tre » cua te, cuu tre, cua triet
sang ma » tang ma, nang ma, sang tao
sach ty » sach y, sach tu, sach thu
ca dam » cao dam, cua dam, ca dao
ca da » ca dao, ca dan, ca dua

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) or (sach ty)) sang ma hoa. hieu van ((ca da) OR (ca dam)) ban thanh toan cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach ty)) sang ma hoa. hieu van ((ca da) OR (ca dam)) ban thanh toan cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sach ty)) sang ma hoa. hieu van ((ca da) OR (ca dam)) ban thanh toan cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach ty)) sang ma hoa. hieu van ((ca da) OR (ca dam)) ban thanh toan cua tre*.