Perhaps you should try some spelling variations:
cao thuc » cao thuoc, bao thuc, can thuc
te sach » toc sach
vai cua » dai cua, hai cua, lai cua
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
tu nong » tu dong, tu cong, tu tong
tu nang » tru nang, tu nano, tu lang
va cao » va cac, va co, va dao

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