Perhaps you should try some spelling variations:
cac khoi » cac khoan, cach thoi, hoc khoi
cac thoi » cac toi, cac hop, cac tro
tang dan » tang van, tung dan, tang luan
va hanh » van hanh, va thanh, va danh
hieu va » lieu va, hieu qua
hieu vu » hieu ve, hieu su, dieu vu
dan hoi » dan hoc, dai hoi, van hoi
xuc va » duc va, tuc va, luc va
vi cua » vai cua, di cua
cua cu » cua chu, cua cau, cua su

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 khoi) or (cac thoi)) tang dan hoi. ((hieu vu) OR (hieu va)) cam xuc va hanh vi cua cu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((cac khoi) OR (cac thoi)) tang dan hoi. ((hieu vu) OR (hieu va)) cam xuc va hanh vi cua cu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((cac khoi) or (cac thoi)) tang dan hoi. ((hieu vu) OR (hieu va)) cam xuc va hanh vi cua cu".
• Adding a wildcard symbol may retrieve word variants: tu ((cac khoi) or (cac thoi)) tang dan hoi. ((hieu vu) OR (hieu va)) cam xuc va hanh vi cua cu*.