Perhaps you should try some spelling variations:
cua triet » cua viet, va triet
tinh viec » tinh viet, dinh viec, sinh viec
su triet » su viet, su tien, ve triet
hieu van » hieu va, thien van, lieu va
va tinh » may tinh
nam soc » nam so, nam moc, nam son
ky sang » ky nang, ky dang, ky tang
ma hoi » mai hoi, ma hoa, me hoi
sac ky » cac ky, sai ky
soc va » hoc va, loc va, doc va
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 sang ((ma hoi) OR (xa hoi)). hieu van nam soc va tinh viec ((cua triet) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky sang ((ma hoi) OR (xa hoi)). hieu van nam soc va tinh viec ((cua triet) OR (su triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky sang ((ma hoi) OR (xa hoi)). hieu van nam soc va tinh viec ((cua triet) or (su triet))".
• Adding a wildcard symbol may retrieve word variants: tu sac ky sang ((ma hoi) OR (xa hoi)). hieu van nam soc va tinh viec ((cua triet) or (su triet))*.