Perhaps you should try some spelling variations:
hieu sau » hieu su, hieu suat, tieu su
sach ky » sac ky, sach y, sach ty
hanh di » hanh vi, hanh de, hang di
tu sach » thu sach, su sach, te sach
cua tre » cua te, cuu tre, cua triet
hieu vu » hieu va, hieu ve, hieu su
luc va » tuc va, loc va
nang o » nang co, nang ho, nang ro
di cua » dai cua, doi cua, de cua
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 ky nang o hoi. ((hieu vu) or (hieu sau)) cham ((luc va) or (duc va)) hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang o hoi. ((hieu vu) OR (hieu sau)) cham ((luc va) OR (duc va)) hanh di cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang o hoi. ((hieu vu) or (hieu sau)) cham ((luc va) or (duc va)) hanh di cua tre*.