Perhaps you should try some spelling variations:
nhanh thi » nhanh thai, nhanh thuc, nhan tai
van nhanh » van thanh, van hanh, van khanh
tu sach » thu sach, su sach, te sach
van dau » van dao, phan dau
thi cua » thai cua, thi cuc, tri cua
duc van » duc va, duc tan, duc manh
van cau » van hau, van chat, toan cau
ty nang » ky nang, ty xang, ty hang
sach ty » sach y, sach tu, sach thu
cua tre » cua te, cuu tre, cua triet
co hoi » co hoc, co loi
o hoi » o hoc, o hai, o hoa

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 hoi)). hieu ((van cau) OR (van dau)) duc van nhanh thi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((o hoi) OR (co hoi)). hieu ((van cau) OR (van dau)) duc van nhanh thi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang ((o hoi) or (co hoi)). hieu ((van cau) OR (van dau)) duc van nhanh thi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((o hoi) or (co hoi)). hieu ((van cau) OR (van dau)) duc van nhanh thi cua tre*.