Perhaps you should try some spelling variations:
mai khoi » mai khoa, tai khoa, cac khoi
chat duc » chat xuc, chat doc, chet duoc
ban hanh » ban hang
ky dang » ky nang, ky danh
mai hoi » dai hoi, lai hoi, mai doi
hieu va » hieu qua
duc ban » duc tan, duc van, dua ban
vi cua » vai cua, di cua
cua te » cua tu

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 ky dang ((mai hoi) or (mai khoi)). ((hieu va) OR (lieu va)) chat duc ban hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu cac ky dang ((mai hoi) OR (mai khoi)). ((hieu va) OR (lieu va)) chat duc ban hanh vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cac ky dang ((mai hoi) or (mai khoi)). ((hieu va) OR (lieu va)) chat duc ban hanh vi cua te".
• Adding a wildcard symbol may retrieve word variants: tu cac ky dang ((mai hoi) or (mai khoi)). ((hieu va) OR (lieu va)) chat duc ban hanh vi cua te*.