Perhaps you should try some spelling variations:
cua triet » cua viet, va triet
su triet » su viet, su tien, ve triet
hieu van » hieu va, thien van, lieu va
van cau » van dau, van hau, van chat
su sach » so sach, vu sach
cau tuc » cau truc, cau tu, cau luc
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
tu sach » thu sach, te sach, tu cach
v nang » va nang, vu nang, van nang
nang o » nang co, nang ho, nang ro
tuc va » thuc va, truc va, tuc xa
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 sach) or (su sach)) v nang o hoi. hieu van cau tuc va hanh di ((cua triet) OR (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) v nang o hoi. hieu van cau tuc va hanh di ((cua triet) OR (su triet))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) v nang o hoi. hieu van cau tuc va hanh di ((cua triet) OR (su triet))*".