Perhaps you should try some spelling variations:
cao hoi » cau hoi, co hoi, cao hoc
hieu va » lieu va, hieu qua
nam luc » nang luc, nhan luc, nam thuc
va tinh » may tinh
vien su » vien sau, vien du, tien su
sac ky » sai ky
va nam » van nam, ha nam, va nay
luc va » duc va, tuc va, loc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sac ky) OR (cac ky)) nang cao hoi. hieu va nam luc va tinh ((vien su) or (nien su)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sac ky) OR (cac ky)) nang cao hoi. hieu va nam luc va tinh ((vien su) OR (nien su)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sac ky) OR (cac ky)) nang cao hoi. hieu va nam luc va tinh ((vien su) or (nien su)) triet".
• Adding a wildcard symbol may retrieve word variants: tu ((sac ky) OR (cac ky)) nang cao hoi. hieu va nam luc va tinh ((vien su) or (nien su)) triet*.