Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu van
hieu va » lieu va, hieu qua
cam tu » cam thu, nam tu, dam tu
va dan » ca dan, va dao, va dau
ca cau » cua cau, cac cau, can cau

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 ky nang cao hoi. ((hieu ve) or (hieu va)) ((cam tu) or (cam xuc)) va dan ca cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang cao hoi. ((hieu ve) OR (hieu va)) ((cam tu) OR (cam xuc)) va dan ca cau tren.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang cao hoi. ((hieu ve) or (hieu va)) ((cam tu) or (cam xuc)) va dan ca cau tren*.