Perhaps you should try some spelling variations:
nhanh thi » nhanh thai, nhanh thuc, nhan tai
va nhanh » va thanh, va hanh, va nhan
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
cao duc » dao duc, cao suc, giao duc
cua tre » cua te, cua triet, dua tren
van cao » van dao, van bao, van hao
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
cuu tre » cau tren, cau treo
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 ty nang ((o hoi) or (co hoc)). hieu van cao duc va nhanh thi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((o hoi) OR (co hoc)). hieu van cao duc va nhanh thi ((cua tre) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((o hoi) or (co hoc)). hieu van cao duc va nhanh thi ((cua tre) or (cuu tre))*.