Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
hanh vai » hanh va, hanh tai, hanh van
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
xang xa » lang xa, mang xa, ang xa
cuu tre » cua tre, cau tren, cau treo
su viet » so viet
cac ly » cac ky, cac le, cam ly

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 ty xang xa hoi. hieu vien cac ly va ((hanh vai) OR (hanh vi)) ((cuu tre) or (su viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty xang xa hoi. hieu vien cac ly va ((hanh vai) OR (hanh vi)) ((cuu tre) OR (su viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty xang xa hoi. hieu vien cac ly va ((hanh vai) OR (hanh vi)) ((cuu tre) or (su viet))".
• Adding a wildcard symbol may retrieve word variants: su sach ty xang xa hoi. hieu vien cac ly va ((hanh vai) OR (hanh vi)) ((cuu tre) or (su viet))*.