Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
hien cac » thien cac, vien cac, hieu cac
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
cac toc » cac toi, cac nuoc, cac thoi
toc van » hoc van, toc san, tac van
su tien » su kien, su hien, tu tieng
x hoi » xa hoi, 5 hoi
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: su sach ky nang ((((x hoi) or (o hoi))) or (x ho)). hieu hien cac toc van hanh vi su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((((x hoi) OR (o hoi))) OR (x ho)). hieu hien cac toc van hanh vi su tien.
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((((x hoi) or (o hoi))) or (x ho)). hieu hien cac toc van hanh vi su tien*.