Perhaps you should try some spelling variations:
can thuc » dan thuc, van thuc, cay thuc
toc sach » hoc sach, doc sach, thuoc sach
hanh hai » thanh hai, nhanh hai, hang hai
day hanh » day nhanh, day thanh, dao hanh
thuc day » thuc dan, thuc vat
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
hieu va » hieu qua
nang xa » nang x, lang xa, nang ma
tu nang » tru nang, tu nong, tu nano

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) tu nang xa hoi. ((hieu va) or (lieu va)) can thuc day hanh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) tu nang xa hoi. ((hieu va) OR (lieu va)) can thuc day hanh hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) tu nang xa hoi. ((hieu va) or (lieu va)) can thuc day hanh hai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) tu nang xa hoi. ((hieu va) or (lieu va)) can thuc day hanh hai cua tre*.