Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
thai cua » than cua, tri cua, dai cua
hieu ve » hieu va, hieu van
va hanh » va thanh, va danh, ban hanh
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai
ve am » va am

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 nang o hoi. hieu ve am thuc ((va hanh) OR (van hanh)) ((tai cuc) or (thai cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky nang o hoi. hieu ve am thuc ((va hanh) OR (van hanh)) ((tai cuc) OR (thai cua)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky nang o hoi. hieu ve am thuc ((va hanh) OR (van hanh)) ((tai cuc) or (thai cua)) triet".
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang o hoi. hieu ve am thuc ((va hanh) OR (van hanh)) ((tai cuc) or (thai cua)) triet*.