Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
cac thuc » cach thuc, can thuc, cay thuc
hang vi » hang va, hanh vi, khang voi
hang di » hang doi, hang dien, hang dich
bo sach » co sach, hoc sach
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
cac thu » cach thuc, cac thoi
y nang » ky nang, ly nang, v nang

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

• Performing a fuzzy search may retrieve terms with similar spellings: bo sach y nang xa hoi. hieu ve ((cac thuc) OR (cac thu)) van ((hang di) or (hang vi)) su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: bo sach y nang xa hoi. hieu ve ((cac thuc) OR (cac thu)) van ((hang di) OR (hang vi)) su triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "bo sach y nang xa hoi. hieu ve ((cac thuc) OR (cac thu)) van ((hang di) or (hang vi)) su triet*".