Perhaps you should try some spelling variations:
nhanh hai » nhanh thai, thanh hai, nhanh ha
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
hanh hai » thanh hai, hang hai, hanh tai
dai hoi » dai hoc, dai hai, dai moi
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
su sac » su sach, su cac, su xac
sac ky » cac ky, sai ky

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 han)). hieu va cac nuoc va ((hanh hai) or (nhanh hai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky nang ((dai hoi) OR (dai han)). hieu va cac nuoc va ((hanh hai) OR (nhanh hai)) cua tre.
• Adding a wildcard symbol may retrieve word variants: su sac ky nang ((dai hoi) or (dai han)). hieu va cac nuoc va ((hanh hai) or (nhanh hai)) cua tre*.