Perhaps you should try some spelling variations:
nang dai » nang dau, nang tai, lang dai
hang hai » hoang hai, hang tai, thanh hai
hanh hai » thanh hai, nhanh hai, hanh tai
cua tre » cua te, cuu tre, cua triet
cac luc » cau luc, coc luc, cac nuoc
hieu va » lieu va, hieu qua
hieu ve » hieu van
dai hoi » dai hoc, dai hai, dai moi
sai ky » sac ky
luc va » duc va, tuc va, loc va
su sai » su tai, su hai, su dai

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

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