Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
doan thi » dan thi, doanh tai, hoang thi
sach ty » sach y, sach tu, sach thu
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
cac tu » cac thu, cach tu, cac du
dan vi » doan vi, don vi, dan va

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 ty) or (sac ky)) lang xa hoi. hieu vien cac tu va ((dan vi) or (doan thi)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ty) OR (sac ky)) lang xa hoi. hieu vien cac tu va ((dan vi) OR (doan thi)) cua tre.
• Adding a wildcard symbol may retrieve word variants: te ((sach ty) or (sac ky)) lang xa hoi. hieu vien cac tu va ((dan vi) or (doan thi)) cua tre*.