Perhaps you should try some spelling variations:
ve triet » va trien, su triet
va triet » va thiet, va trien, cua triet
dang xay » dang van, van xay
hang di » hang doi, hang vi, hang dien
va hang » van hang, va nang, va lang
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
lang xa » lang ha, lang van
cac toc » cac toi, cac nuoc, cac thoi
toc va » hoc va, toc ta, tuc va

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((lang xa) OR (dang xay)) hoi. hieu va cac toc va hang di ((va triet) OR (ve triet))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((lang xa) OR (dang xay)) hoi. hieu va cac toc va hang di ((va triet) or (ve triet))~".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((lang xa) OR (dang xay)) hoi. hieu va cac toc va hang di ((va triet) or (ve triet))*.