Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
vu sach » vu bach, su sach, vu khach
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
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.

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