Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
hieu van » hieu va, thien van, lieu va
hanh dan » thanh dan, hanh san, canh dan
toc sach » hoc sach, doc sach, thuoc sach
thuc day » thuc dan, thuc vat
thuc va » thuc vat, thuc dan
nang ho » nang hoc, nang co, tang ho
ho hoc » hoa hoc, cho hoc, hoi hoc
dan su » dang su
van am » van nam, van lam, van dam

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) ky nang ho hoc. hieu van am ((thuc va) OR (thuc day)) hanh dan su triet~.
• 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) OR (thuc day)) hanh dan 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) OR (thuc day)) hanh dan su triet".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ky nang ho hoc. hieu van am ((thuc va) OR (thuc day)) hanh dan su triet*.