Perhaps you should try some spelling variations:
cau thuc » cau truc, cuu thuc, can thuc
hanh tai » thanh tai, hang tai, han tai
tu sach » thu sach, te sach, tu cach
tai cua » thai cua, tai cuc, tri cua
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, nang ma
tu nang » tru nang, tu nong, tu nano
su sach » so sach, vu sach

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

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