Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
van hanh » ban hanh, van anh, van ban
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
cac toc » cac toi, cac nuoc, cac thoi
su tien » su kien, su hien, tu tieng
5 hoi » o hoi
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 ((5 hoi) or (x ho)). hieu vien cac toc ((van hanh) OR (van thanh)) vi su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((5 hoi) OR (x ho)). hieu vien cac toc ((van hanh) OR (van thanh)) vi su tien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((5 hoi) or (x ho)). hieu vien cac toc ((van hanh) OR (van thanh)) vi su tien".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((5 hoi) or (x ho)). hieu vien cac toc ((van hanh) OR (van thanh)) vi su tien*.