Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
vu sach » vu bach, su sach, vu khach
hieu va » lieu va, hieu qua
hanh di » hanh de, hang di, danh di
thuc va » thuc vat, thuc dan, thuc day
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu van
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van 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: vu sach v nang x hoi. ((hieu ve) OR (hieu va)) nam thuc va ((hanh di) OR (hanh vi)) cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach v nang x hoi. ((hieu ve) or (hieu va)) nam thuc va ((hanh di) OR (hanh vi)) cua tre~".
• Adding a wildcard symbol may retrieve word variants: vu sach v nang x hoi. ((hieu ve) or (hieu va)) nam thuc va ((hanh di) OR (hanh vi)) cua tre*.