Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien dai » hien dai
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » lang xa, nang ma, mang xa
va dinh » van dinh, va kinh, va tinh
cua tre » cua te, cuu tre, cua triet
dai lo » dai so, dai ly, dai o

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