Perhaps you should try some spelling variations:
nang cau » nang cao, hang cau, nang dau
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cam duc » cam xuc, cao duc, pham duc
hieu va » lieu va, hieu qua
hieu ve » hieu van
cau hoa » cau hoi
cua suc » cua duc, cua tuc, cua cuc
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
cua su » qua su

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 cau hoa. ((hieu ve) OR (hieu va)) cam duc va dan vi ((cua su) or (cua suc))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang cau hoa. ((hieu ve) OR (hieu va)) cam duc va dan vi ((cua su) OR (cua suc))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang cau hoa. ((hieu ve) OR (hieu va)) cam duc va dan vi ((cua su) or (cua suc))*".