Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien sach » vien bach, dien sach, viet sach
sach dao » lanh dao
dang xay » dang van, van xay
va danh » va dinh, va hanh, dia danh
cua tre » cua te, cuu tre, cua triet
lang xa » lang ha, lang van
va dan » ca dan, va dao, va dau
de cua » le cua, te cua, dieu cua
su cac » tu cac, su cao, su can

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su cac ky ((lang xa) or (dang xay)) hoi. hieu vien sach dao ((va danh) or (va dan)) de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su cac ky ((lang xa) OR (dang xay)) hoi. hieu vien sach dao ((va danh) OR (va dan)) de cua tre.
• Adding a wildcard symbol may retrieve word variants: su cac ky ((lang xa) or (dang xay)) hoi. hieu vien sach dao ((va danh) or (va dan)) de cua tre*.