Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
van thanh » ban thanh, van tuan
thu sach » tu sach, thuat sach, thuoc sach
tai cua » thai cua, tai cuc, tri cua
duc van » duc va, duc tan, duc manh
cua tre » cua te, cuu tre, cua triet
lang xa » lang ha, dang xay, lang van
nang ma » tang ma, sang ma, nang cao
va cao » va cac, va dao, va bao
va co » vo co

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

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