Perhaps you should try some spelling variations:
va hanh » van hanh, va thanh, va danh
dai hoi » dai hai, dai moi
hoi cua » hoi chuc
hai cua » thai cua, dai cua, lai cua
hieu ve » hieu va, hieu van
cac luc » cau luc, coc luc, cac nuoc
su sac » su sach, su cac, su xac
luc va » duc va, tuc va, loc va
sac ky » cac ky, sai ky
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sac ky nang ((dai hoi) or (dai hoc)). hieu ve cac luc va hanh ((hai cua) OR (hoi cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky nang ((dai hoi) OR (dai hoc)). hieu ve cac luc va hanh ((hai cua) OR (hoi cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ky nang ((dai hoi) or (dai hoc)). hieu ve cac luc va hanh ((hai cua) OR (hoi cua)) tre".
• Adding a wildcard symbol may retrieve word variants: su sac ky nang ((dai hoi) or (dai hoc)). hieu ve cac luc va hanh ((hai cua) OR (hoi cua)) tre*.