Perhaps you should try some spelling variations:
hieu toan » bieu toan, thien toan, kiem toan
tu tuong » tu dong
toan can » toan ban, toan cao, toan cau
can thuc » dan thuc, van thuc, cay thuc
vat hanh » vat thanh, van hanh, nhat hanh
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
ca tren » cau tren, cu tren, la tren
va hanh » van hanh, va thanh, va danh
su sac » su sach, su cac, su xac
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sac ky tang xa hoi. hieu toan can thuc ((vat hanh) or (va hanh)) va ((ca tren) or (tu tuong))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky tang xa hoi. hieu toan can thuc ((vat hanh) OR (va hanh)) va ((ca tren) OR (tu tuong)).
• Adding a wildcard symbol may retrieve word variants: su sac ky tang xa hoi. hieu toan can thuc ((vat hanh) or (va hanh)) va ((ca tren) or (tu tuong))*.