Perhaps you should try some spelling variations:
nang dai » nang dau, nang tai, lang dai
hanh vai » hanh vi, hanh va, hanh tai
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
cac luc » coc luc, cac nuoc, cac cuoc
vai cua » dai cua, hai cua, lai cua
va hanh » van hanh, va thanh, va danh
cau luc » cau truc, cau phuc
hieu ve » hieu va
sach ky » sac ky, sach y, sach ty
dai hoi » dai hoc, dai hai, dai moi
cua tre » cua te, cuu tre, cua triet

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang dai hoi. ((hieu ve) OR (hieu van)) ((cac luc) or (cau luc)) va hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang dai hoi. ((hieu ve) OR (hieu van)) ((cac luc) OR (cau luc)) va hanh vai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang dai hoi. ((hieu ve) OR (hieu van)) ((cac luc) or (cau luc)) va hanh vai cua tre*".