Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
van hanh » van thanh, ban hanh, van anh
hieu van » hieu va, thien van, lieu va
toc sach » hoc sach, doc sach, thuoc sach
nang ho » nang hoc, nang co, tang ho
va hanh » va thanh, va danh, ban hanh
ho hoc » hoa hoc, cho hoc, hoi hoc
van am » van nam, van lam, van dam
dai su » dai sua, dai so, dan su

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky nang ho hoc. hieu van am thuc ((va hanh) OR (van hanh)) dai su triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ky nang ho hoc. hieu van am thuc ((va hanh) OR (van hanh)) dai su triet~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ky nang ho hoc. hieu van am thuc ((va hanh) OR (van hanh)) dai su triet*.