Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
su triet » su viet, su tien, ve triet
te sach » toc sach
hieu ve » hieu va, hieu van
cac duc » cac du, cao duc, cac dac
duc van » duc va, duc tan, duc manh
v nang » va nang, vu nang, van nang
ve cac » va cac, vien cac
x hoi » xa hoi, o hoi, x ho
vi su » va su, ve su, ki su

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ((v nang) or (cam nang)) x hoi. hieu ve cac duc van hanh vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((v nang) OR (cam nang)) x hoi. hieu ve cac duc van hanh vi su triet*.