Perhaps you should try some spelling variations:
cac cau » cac mau, bac cau, cac cam
cam thu » nam thu, cac thu, ca thu
hieu ve » hieu va, hieu van
tu cach » tu cac
cao hoi » cau hoi, co hoi, cao hoc
tu sach » thu sach, su sach, te sach
thu va » thuc va, thue va, tu va
va dan » ca dan, va dao, va dau
ca cau » cua cau, can cau, ca cac
ve cam » ve cham, ve cac, va cam

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

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