Perhaps you should try some spelling variations:
su triet » su tien, ve triet
tinh doi » trinh doc, trinh do, tinh hoc
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
va tinh » may tinh
cac toc » cac toi, cac nuoc, cac thoi
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
su viet » so viet
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: so sach ky ((lang xa) OR (van xay)) hoi. hieu va cac toc va tinh doi ((su triet) OR (su viet))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky ((lang xa) or (van xay)) hoi. hieu va cac toc va tinh doi ((su triet) OR (su viet))~".
• Adding a wildcard symbol may retrieve word variants: so sach ky ((lang xa) or (van xay)) hoi. hieu va cac toc va tinh doi ((su triet) OR (su viet))*.