Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
hieu van » hieu va, thien van, lieu va
hanh lai » hanh lam, hanh tai, thanh lap
van hanh » van thanh, ban hanh, van anh
cham duc » cham soc, pham duy, phan duc
sach ky » sac ky, sach y, sach ty
lai cua » dai cua, hai cua, lai chau
tu sach » thu sach, su sach, te sach
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 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 ky nang ((x hoi) or (o hoi)). hieu van ((cham duc) OR (pham duc)) van hanh lai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((x hoi) OR (o hoi)). hieu van ((cham duc) OR (pham duc)) van hanh lai cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((x hoi) or (o hoi)). hieu van ((cham duc) OR (pham duc)) van hanh lai cua viet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((x hoi) or (o hoi)). hieu van ((cham duc) OR (pham duc)) van hanh lai cua viet*.