Perhaps you should try some spelling variations:
cac khoa » cac khoan, cac khoi, dac khoa
ban hanh » ban hang
ve cham » va cham, ve chat, vu cham
cua tre » cua te, cua triet, dua tren
hanh di » hanh vi, hanh de, hang di
cham so » cham soc, cham o, ham so
hieu ve » hieu va, hieu van
tang ma » tang van
cuu tre » cau tren, cau treo
so ban » sao ban, so bang, co ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu cac khoa ((tang ma) OR (mang may)) hoi. hieu ve cham so ban hanh di ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu cac khoa ((tang ma) OR (mang may)) hoi. hieu ve cham so ban hanh di ((cua tre) OR (cuu tre))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cac khoa ((tang ma) OR (mang may)) hoi. hieu ve cham so ban hanh di ((cua tre) or (cuu tre))*".