Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
bo sach » co sach, hoc sach
hieu ve » hieu va, hieu van
cac tuc » cac toc, cac tu, cac tac
tuc van » thuc van, truc van, tuc va
hang di » hang doi, hang dien, hang dich
hang vi » hang va, hanh vi, khang voi
y nang » ly nang, v nang, may nang
ve cac » va cac, vien cac

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) OR (ky nang)) xa hoi. hieu ve cac tuc 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) OR (ky nang)) xa hoi. hieu ve cac tuc 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) OR (ky nang)) xa hoi. hieu ve cac tuc van ((hang di) or (hang vi)) su triet*".