Perhaps you should try some spelling variations:
so sach » so sanh, bo sach, co sach
hieu va » lieu va, hieu qua
hang di » hang doi, hang dien, hang dich
hang vi » hang va, hanh vi, khang voi
co viet » so viet, o viet, hoc viet
y nang » ky nang, ly nang, v nang
cac tu » cac thu, cach tu, cac du
tu van » tu va
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 cac tu van ((hang di) OR (hang vi)) co viet~.
• Adding a wildcard symbol may retrieve word variants: so sach y nang x hoi. hieu va cac tu van ((hang di) or (hang vi)) co viet*.