Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
hang vai » hang tai, hang hai, hang vi
duc ban » duc tan, duc van, dua ban
cac duc » cac du, cao duc, cac dac
tu sach » thu sach, su sach, te sach
cua tre » cua te, cuu tre, cua triet
nang xa » lang xa, nang ma, mang xa

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