Perhaps you should try some spelling variations:
xa thanh » va thanh, ha thanh, ta thanh
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
nam tuc » nam thuc, nam truc, nam tu
xa hanh » xa khanh, va hanh, da hanh
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
x hoi » xa hoi, o hoi, 5 hoi

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 nang ((x hoi) OR (x ho)). hieu van nam tuc ((xa hanh) or (xa thanh)) vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((x hoi) OR (x ho)). hieu van nam tuc ((xa hanh) OR (xa thanh)) vai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang ((x hoi) OR (x ho)). hieu van nam tuc ((xa hanh) or (xa thanh)) vai cua tre*".