Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh tai » thanh tai, hang tai, han tai
ban hanh » ban hang
tu sach » thu sach, su sach, te sach
tai cua » thai cua, tai cuc, tri cua
xuc ban » duc ban, cuc ban, quoc ban
cac xuc » cam xuc, cac nuoc, chat xuc
cua tre » cua te, cuu tre, cua triet
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va
cho hoc » co hoc, khoa hoc
cao hoc » co hoc, chat hoc

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 xang ((cao hoc) or (cho hoc)). ((hieu ve) OR (hieu van)) cac xuc ban hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty xang ((cao hoc) OR (cho hoc)). ((hieu ve) OR (hieu van)) cac xuc ban hanh tai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty xang ((cao hoc) or (cho hoc)). ((hieu ve) OR (hieu van)) cac xuc ban hanh tai cua tre*".