Perhaps you should try some spelling variations:
thuc day » thuc dan, thuc vat
cua viet » hoa viet, cua vat, cua dieu
dinh vai » dinh van, dinh vi, dinh va
tu sach » thu sach, su sach, te sach
ca viet » va viet, co viet, hoa viet
thuc va » thuc vat, thuc dan
y nang » ky nang, ly nang, v nang
qua am » quan am, qua ap, cua am
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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: tu sach y nang o hoi. hieu qua am ((thuc va) OR (thuc day)) dinh vai ((cua viet) OR (ca viet))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang o hoi. hieu qua am ((thuc va) or (thuc day)) dinh vai ((cua viet) OR (ca viet))~".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang o hoi. hieu qua am ((thuc va) or (thuc day)) dinh vai ((cua viet) OR (ca viet))*.