Perhaps you should try some spelling variations:
dat duoc » dat nuoc, da duoc, luat duoc
mai hoi » mai khoi, dai hoi, lai hoi
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
duoc va » nuoc va, duc va, duoc ma
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
sac ky » sai ky
ve dat » de dat, va dat, ve dao
ma hoi » xa hoi, ma hoa, me hoi
di cua » dai cua, doi cua, de cua

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 ky) or (cac ky)) nang ((ma hoi) OR (mai hoi)). hieu ve dat duoc va hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu ((sac ky) OR (cac ky)) nang ((ma hoi) OR (mai hoi)). hieu ve dat duoc va hanh di cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu ((sac ky) or (cac ky)) nang ((ma hoi) OR (mai hoi)). hieu ve dat duoc va hanh di cua tre*".