Perhaps you should try some spelling variations:
dang xay » dang van, van xay
tu sach » thu sach, su sach, te sach
vai cua » dai cua, hai cua, lai cua
dao vai » dao van, dao va, dao bai
cac tac » cac toc, cac bac, cac dac
cac tuc » cac toc, cac tu, cac nuoc
lang xa » lang ha, lang van
cua tre » cua te, cuu tre, cua triet
va dao » ca dao

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 ((lang xa) or (dang xay)) hoi. hieu qua ((cac tuc) OR (cac tac)) va dao vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((lang xa) OR (dang xay)) hoi. hieu qua ((cac tuc) OR (cac tac)) va dao vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((lang xa) or (dang xay)) hoi. hieu qua ((cac tuc) OR (cac tac)) va dao vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((lang xa) or (dang xay)) hoi. hieu qua ((cac tuc) OR (cac tac)) va dao vai cua tre*.