Perhaps you should try some spelling variations:
hanh tai » thanh tai, hang tai, han tai
hieu cua » hieu qua, dieu cua, bieu cua
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
tai cua » thai cua, tai cuc, tri cua
quan va » quan vi, quan ha, luan va
hieu ca » hieu cac, hieu va, hieu xa
cua tre » cua te, cuu tre, cua triet
qua va » qua van, vua va, qua ca
x hoi » xa hoi, o hoi, x ho

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 ky nang x hoi. ((hieu ca) or (hieu cua)) nam ((qua va) OR (quan va)) hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang x hoi. ((hieu ca) OR (hieu cua)) nam ((qua va) OR (quan va)) hanh tai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang x hoi. ((hieu ca) or (hieu cua)) nam ((qua va) OR (quan va)) hanh tai cua tre*".