Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc anh
dieu cua » dieu tra
han dieu » nhan dieu, than dieu, lan dieu
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
vu nang » vuc nang, va nang, vu dang
hoc cac » hoc cao
cua tre » cua te, cuu tre, cua triet
luc va » duc va, loc va
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((hoc sach) or (hoc cac)) vu nang xa hoi. hieu va cac ((luc va) OR (tuc va)) han dieu cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc sach) OR (hoc cac)) vu nang xa hoi. hieu va cac ((luc va) OR (tuc va)) han dieu cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((hoc sach) or (hoc cac)) vu nang xa hoi. hieu va cac ((luc va) OR (tuc va)) han dieu cua tre".
• Adding a wildcard symbol may retrieve word variants: ((hoc sach) or (hoc cac)) vu nang xa hoi. hieu va cac ((luc va) OR (tuc va)) han dieu cua tre*.