Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
dat hang » dat khanh, dat quang, tat thang
day hang » dai hang, day nang, dai thang
doi cua » dai cua, hoi cua, dong cua
su sach » so sach
hieu ve » hieu va, hieu van
vu sach » vu bach, vu khach
cua tre » cua te, cuu tre, cua triet
ve nam » he nam, va nam, le nam
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.

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