Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
vu khach » vu khanh, vu khac, vay khach
thuc van » thuc vat, thuc dan, thuc va
nam thuc » nam thuoc, am thuc, nam thu
vu sach » vu bach, su sach
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu van
y nang » ky nang, ly nang, v nang
vi cua » vai cua, di cua
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) OR (vu khach)) y nang x hoi. ((hieu ve) or (hieu va)) nam thuc van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sach) OR (vu khach)) y nang x hoi. ((hieu ve) OR (hieu va)) nam thuc van hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu sach) OR (vu khach)) y nang x hoi. ((hieu ve) or (hieu va)) nam thuc van hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((vu sach) OR (vu khach)) y nang x hoi. ((hieu ve) or (hieu va)) nam thuc van hanh vi cua tre*.