Perhaps you should try some spelling variations:
chat thuc » thuat thuc, nhan thuc, chat thai
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu va, hieu van
ve chat » va chat, van chat
thuc va » thuc vat, thuc dan, thuc day
cua cau » cua cac, cua chu, cua cay
va dan » ca dan, va dao, va dau
ca cau » cac cau, can cau, ca cac

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)) ky nang cao hoi. hieu ve chat thuc va dan ((ca cau) OR (cua cau)) tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky nang cao hoi. hieu ve chat thuc va dan ((ca cau) OR (cua cau)) tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) ky nang cao hoi. hieu ve chat thuc va dan ((ca cau) OR (cua cau)) tren".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky nang cao hoi. hieu ve chat thuc va dan ((ca cau) OR (cua cau)) tren*.