Perhaps you should try some spelling variations:
hieu vien » hieu viec, thieu nien, hieu tieng
hieu hien » bieu hien, dieu hien, chieu chien
van dinh » van minh, van dich, xuan dinh
tu sach » thu sach, su sach, te sach
vai cua » dai cua, hai cua, lai cua
va dinh » va kinh, va tinh, vu dinh
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, nang ma
sach ky » sac ky, sach y, sach ty
cac lo » cac lop, cac co, cac bo

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