Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
vien cua » viec cua, dien cua, tien cua
nam luc » nang luc, nhan luc, nam thuc
hieu va » lieu va, hieu qua
tang ma » tang van
sac ky » cac ky, sai ky
va nam » van nam, ha nam, va nay
tu sac » tu sach, tu cac, tu san

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