Perhaps you should try some spelling variations:
tan hang » tan khang, ban hang, van hang
hang vai » hang va, hang tai, hang hai
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
cao duc » dao duc, cao suc, giao duc
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
ve cao » va cao, ve bao, ve cac
x hoi » xa hoi, x ho, 5 hoi
o hoi » co hoi, o hoc, o hai

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 (o hoi)). hieu ve cao duc tan hang vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((x hoi) OR (o hoi)). hieu ve cao duc tan hang vai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((x hoi) or (o hoi)). hieu ve cao duc tan hang vai cua tre*.