Perhaps you should try some spelling variations:
mai hoi » mai khoi, dai hoi, lai hoi
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
vu sac » vu sach, vu san, vu cac
va sac » va cac, va suc, va san
ma hoi » xa hoi, ma hoa, me hoi
va dat » va dao, va dau, va dap
vi cua » vai cua, di cua
nuoc » quoc, duoc, ngoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((vu sac) or (va sac)) ky nang ((ma hoi) OR (mai hoi)). hieu va dat nuoc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sac) OR (va sac)) ky nang ((ma hoi) OR (mai hoi)). hieu va dat nuoc va hanh vi cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu sac) or (va sac)) ky nang ((ma hoi) OR (mai hoi)). hieu va dat nuoc va hanh vi cua tre*".