Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
cac cau » cac mau, bac cau, ca cau
dan cac » dan cach, dang cac, dan ca
cam tuc » cam tu, nam thuc, dam thuc
hieu ve » hieu va, hieu van
tu sach » thu sach, te sach, tu cach
cao hoi » cau hoi, co hoi, cao hoc
su sach » so sach, vu sach
va dan » ca dan, va dao, va dau

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 ((cam tuc) OR (cam xuc)) va dan cac 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 ((cam tuc) OR (cam xuc)) va dan cac 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 ((cam tuc) OR (cam xuc)) va dan cac cau tren".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky nang cao hoi. hieu ve ((cam tuc) OR (cam xuc)) va dan cac cau tren*.