Perhaps you should try some spelling variations:
hieu vien » hieu viec, thieu nien, hieu tieng
hieu hien » bieu hien, dieu hien, chieu chien
cach bao » cach nao, sach bao, cach giao
tu sach » thu sach, su sach, te sach
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
cac bao » cac bai, cac ban, cac bac
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
di cua » dai cua, doi cua, de cua
x hoi » xa hoi, o hoi, x ho

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. ((hieu vien) or (hieu hien)) ((cac bao) OR (cach bao)) va hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang x hoi. ((hieu vien) OR (hieu hien)) ((cac bao) OR (cach bao)) va hanh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang x hoi. ((hieu vien) or (hieu hien)) ((cac bao) OR (cach bao)) va hanh di cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x hoi. ((hieu vien) or (hieu hien)) ((cac bao) OR (cach bao)) va hanh di cua tre*.