Perhaps you should try some spelling variations:
cac thoi » cac toi, cac hop, cac tro
hoc khoi » hoc khoa, hoc hoa, hoc noi
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
dan hoi » dai hoi, van hoi, dang khoi
dan hoc » van hoc, dan toc, dai hoc
vi cua » vai cua, di cua
xuc va » duc va, tuc va, luc va
cua su » qua su
va cam » va cham, va cac, va cao

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

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