Perhaps you should try some spelling variations:
hieu vien » hieu viec, thieu nien, hieu tieng
hieu hien » bieu hien, dieu hien, chieu chien
dinh vai » dinh van, dinh vi, dinh va
te sach » toc sach
vai cua » dai cua, hai cua, lai cua
va dinh » van dinh, va kinh, va tinh
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
cac le » cach le, cac he, mac le
cac ly » cac ky, cam ly, cap ly

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky nang xa hoi. ((hieu vien) OR (hieu hien)) ((cac ly) or (cac le)) va dinh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang xa hoi. ((hieu vien) OR (hieu hien)) ((cac ly) OR (cac le)) va dinh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang xa hoi. ((hieu vien) OR (hieu hien)) ((cac ly) or (cac le)) va dinh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ky nang xa hoi. ((hieu vien) OR (hieu hien)) ((cac ly) or (cac le)) va dinh vai cua tre*.