Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
sach ky » sac ky, sach y, sach ty
cua cau » cua cac, cua chu, cua cay
tu sach » thu sach, su sach, te sach
hieu va » hieu qua
cao hoi » cau hoi, co hoi, cao hoc
cam tuc » cam xuc, cam tu, nam thuc
va dan » va dao, va dau, va dap
ca dan » cac dan, ca dao

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 va) OR (lieu va)) cam tuc ((va dan) or (ca dan)) cua cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang cao hoi. ((hieu va) OR (lieu va)) cam tuc ((va dan) OR (ca dan)) cua cau tren*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang cao hoi. ((hieu va) OR (lieu va)) cam tuc ((va dan) or (ca dan)) cua cau tren*".