Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
su triet » su viet, su tien, ve triet
co sach » bo sach, cuon sach, hoc sach
sach ky » sac ky, sach y, sach ty
vuc van » duc van, luc van, thuc van
ve cac » vien cac
o hoi » co hoi, o hoc, o hai
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: co sach ky nang ((o hoi) or (xa hoi)). hieu ((ve cac) or (va cac)) vuc van hanh vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: co sach ky nang ((o hoi) OR (xa hoi)). hieu ((ve cac) OR (va cac)) vuc van hanh vi su triet.
• Adding a wildcard symbol may retrieve word variants: co sach ky nang ((o hoi) or (xa hoi)). hieu ((ve cac) or (va cac)) vuc van hanh vi su triet*.