Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
tu cach » tu cac
te sach » toc sach
hieu va » lieu va, hieu qua
nang o » nang co, nang ho, nang ro
tu cua » hu cua, vu cua
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu cach) or (te sach)) ky nang o hoi. hieu va cac nuoc ((va danh) OR (va hanh)) tu cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cach) OR (te sach)) ky nang o hoi. hieu va cac nuoc ((va danh) OR (va hanh)) tu cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu cach) or (te sach)) ky nang o hoi. hieu va cac nuoc ((va danh) OR (va hanh)) tu cua triet".
• Adding a wildcard symbol may retrieve word variants: ((tu cach) or (te sach)) ky nang o hoi. hieu va cac nuoc ((va danh) OR (va hanh)) tu cua triet*.