Perhaps you should try some spelling variations:
so sach » so sanh, bo sach, co sach
tuc van » thuc van, truc van, tuc va
hang vi » hang va, hanh vi, khang voi
hang di » hang doi, hang dien, hang dich
cac tuc » cac toc, cac tu, cac tac
hieu va » lieu va
co viet » so viet, o viet, hoc viet
y nang » ky nang, ly nang, v nang
x hoi » xa hoi, o hoi, x ho

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 y nang x hoi. ((hieu va) OR (hieu qua)) cac tuc van ((hang di) OR (hang vi)) co viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y nang x hoi. ((hieu va) OR (hieu qua)) cac tuc van ((hang di) or (hang vi)) co viet~".
• Adding a wildcard symbol may retrieve word variants: so sach y nang x hoi. ((hieu va) OR (hieu qua)) cac tuc van ((hang di) or (hang vi)) co viet*.