Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
va thanh » gia thanh, ban thanh, va tinh
tu sach » thu sach, su sach, te sach
cua tre » cuu tre, cua triet, dua tren
cao duc » dao duc, cao suc, giao duc
hieu va » lieu va, hieu qua
sach ty » sach y, sach tu, sach thu
lang xa » lang ha, dang xay, lang van
tang ma » mang may, tang van
va cao » va cac, va co, va dao
cua te » cua tu

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