Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
cac tac » cac toc, cac dac, cac tai
dao vai » dao van, dao bai, dao hai
sach ty » sach y, sach tu, sach thu
cac bac » cac bai, cac ban, cac cach
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
ty lang » tay lang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
dao va » dao van, tao va, do va

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