Perhaps you should try some spelling variations:
hang doi » hang di, hang loi, huong doi
cua viet » ca viet, hoa viet, cua vat
so sach » so sanh, bo sach, co sach
hieu va » lieu va, hieu qua
hang vi » hanh vi, hang di, khang voi
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 doi) OR (((hang vi) OR (hang va)))) cua viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y nang x hoi. hieu va cac tu van ((hang doi) or (((hang vi) OR (hang va)))) cua viet~".
• Adding a wildcard symbol may retrieve word variants: so sach y nang x hoi. hieu va cac tu van ((hang doi) or (((hang vi) OR (hang va)))) cua viet*.