Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
su sach » vu sach
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
so sach » so sanh, bo sach, co sach
ve cam » ve cham, ve cac, va cam
y nang » ky nang, ly nang, v nang
vi cua » vai cua, di cua
x hoi » xa hoi, x ho, 5 hoi
o hoi » co hoi, o hoc, o hai

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