Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
cua viet » ca viet, hoa viet, cua vat
hanh vai » hanh vi, hanh va, hanh tai
van hanh » van thanh, ban hanh, van anh
su triet » su viet, su tien, ve triet
hieu ve » hieu va
sach ky » sac ky, sach y, sach ty
cac luc » cau luc, coc luc, cac nuoc
luc van » luoc van, luu van, duc van
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang

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 ky lang xa hoi. ((hieu ve) or (hieu van)) cac luc van hanh vai ((cua viet) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky lang xa hoi. ((hieu ve) OR (hieu van)) cac luc van hanh vai ((cua viet) OR (su triet)).
• Adding a wildcard symbol may retrieve word variants: toc sach ky lang xa hoi. ((hieu ve) or (hieu van)) cac luc van hanh vai ((cua viet) or (su triet))*.