Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
nam luc » nang luc, nhan luc, nam thuc
vien su » vien sau, nien su, vien du
sac ky » sai ky
ma hoi » mai hoi, xa hoi, ma hoa
va nam » van nam, ha nam, va nay

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