Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
cua triet » cua viet, su triet, va triet
dang xay » dang van, van xay
nam thuc » nam thuoc, am thuc, nam thu
lang xa » lang ha, lang van
vai cua » dai cua, hai cua, lai cua
so sach » so sanh, bo sach, co sach
va dan » ca dan, va dau, va dap
va dao » ca dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y ((lang xa) or (dang xay)) hoi. hieu quang nam thuc ((va dan) OR (va dao)) vai cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y ((lang xa) OR (dang xay)) hoi. hieu quang nam thuc ((va dan) OR (va dao)) vai cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y ((lang xa) or (dang xay)) hoi. hieu quang nam thuc ((va dan) OR (va dao)) vai cua triet".
• Adding a wildcard symbol may retrieve word variants: so sach y ((lang xa) or (dang xay)) hoi. hieu quang nam thuc ((va dan) OR (va dao)) vai cua triet*.