Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dang xay » dang van, van xay
su triet » su tien, ve triet
xay hoi » xa hoi, tay hoi, cay phoi
hieu ve » hieu va, hieu van
xuc may » xuc hay, truc may, phuc may
dinh ve » dinh ket
su viet » so viet
y dang » ky dang, 2 dang, _ dang
ve cam » ve cham, ve cac, va cam

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach y dang xay hoi. hieu ve cam xuc may ((dinh ve) OR (dinh van)) ((su triet) or (su viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y dang xay hoi. hieu ve cam xuc may ((dinh ve) OR (dinh van)) ((su triet) OR (su viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y dang xay hoi. hieu ve cam xuc may ((dinh ve) OR (dinh van)) ((su triet) or (su viet))".
• Adding a wildcard symbol may retrieve word variants: toc sach y dang xay hoi. hieu ve cam xuc may ((dinh ve) OR (dinh van)) ((su triet) or (su viet))*.