Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
vanh dai » van dai, vanh tai, lanh dao
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
cao hoi » cau hoi, co hoi, cao hoc
van cam » van nam, van lam, van dam
van cau » van dau, van hau, van chat
thuc va » thuc vat, thuc dan, thuc day
va vanh » va van, va danh, va hanh

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 (hoc sach)) ky nang cao hoi. thien ((van cam) or (van cau)) thuc va vanh dai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (hoc sach)) ky nang cao hoi. thien ((van cam) OR (van cau)) thuc va vanh dai cua viet.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (hoc sach)) ky nang cao hoi. thien ((van cam) or (van cau)) thuc va vanh dai cua viet*.