Perhaps you should try some spelling variations:
day hanh » day nhanh, day thanh, dao hanh
thuc day » thuc dan, thuc vat
nam thuc » nam thuoc, am thuc, nam thu
su sach » so sach
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu van
nang xa » nang x, lang xa, nang ma
vu sach » vu bach, vu khach
y nang » ky nang, ly nang, v nang
vi cua » vai cua, di cua

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