Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
van thanh » ban thanh, van tuan
tu sach » thu sach, su sach, te sach
tai cua » thai cua, tai cuc, tri cua
duc van » duc va, duc tan, duc manh
cao duc » dao duc, cao suc, giao duc
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va
lang xa » lang ha, dang xay, lang van
nang ma » tang ma, sang ma, nang 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 y ((nang ma) or (lang xa)) hoi. ((hieu va) OR (hieu qua)) cao duc van thanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang ma) OR (lang xa)) hoi. ((hieu va) OR (hieu qua)) cao duc van thanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((nang ma) or (lang xa)) hoi. ((hieu va) OR (hieu qua)) cao duc van thanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang ma) or (lang xa)) hoi. ((hieu va) OR (hieu qua)) cao duc van thanh tai cua tre*.