Perhaps you should try some spelling variations:
cau thuc » cau truc, cuu thuc, can thuc
tu sach » thu sach, su sach, tu cach
co sach » bo sach, cuon sach, hoc sach
te sach » toc sach
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu va, hieu van
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
cua tre » cua te, cuu tre, cua triet
ve cau » ke cau, va cau, ve cac
di cua » dai cua, doi cua, de cua

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 (co sach))) or (te sach)) ky nang cao hoi. hieu ve cau thuc va hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((tu sach) OR (co sach))) OR (te sach)) ky nang cao hoi. hieu ve cau thuc va hanh di cua tre.
• Adding a wildcard symbol may retrieve word variants: ((((tu sach) or (co sach))) or (te sach)) ky nang cao hoi. hieu ve cau thuc va hanh di cua tre*.