Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
su sach » so sach, vu sach
hanh de » hanh ve, hanh kem
hanh di » hanh vi, hang di, danh di
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
hieu ve » hieu van
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.

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