Perhaps you should try some spelling variations:
day hanh » day nhanh, day thanh, dao hanh
thuc day » thuc dan, thuc vat
nam thuc » nam thuoc, am thuc, nam thu
hieu ve » hieu va, hieu van
hanh di » hanh vi, hanh de, hang di
su sach » so sach
cua tre » cua te, cuu tre, cua triet
vu sach » vu bach, vu khach
ve nam » he nam, va nam, le nam
y nang » ky nang, ly nang, v nang
di cua » dai cua, doi cua, de cua
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (vu sach)) y nang ((x hoi) OR (o hoi)). hieu ve nam thuc day hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) y nang ((x hoi) OR (o hoi)). hieu ve nam thuc day hanh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (vu sach)) y nang ((x hoi) OR (o hoi)). hieu ve nam thuc day hanh di cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) y nang ((x hoi) OR (o hoi)). hieu ve nam thuc day hanh di cua tre*.