Perhaps you should try some spelling variations:
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
cuc tre » duc tre, cua tre, cuu tre
hieu ve » hieu va, hieu van
cac xuc » cam xuc, chat xuc, cac cuoc
tu san » thu san, tu ban, tu can
san ky » sang ky, van ky, dan ky
o hai » co hai, so hai, o lai
o hoi » co hoi, o hoc, o hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu san ky nang ((o hoi) or (o hai)). hieu ve ((cac xuc) or (cac nuoc)) van hanh tai cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu san ky nang ((o hoi) OR (o hai)). hieu ve ((cac xuc) OR (cac nuoc)) van hanh tai cuc tre.
• Adding a wildcard symbol may retrieve word variants: tu san ky nang ((o hoi) or (o hai)). hieu ve ((cac xuc) or (cac nuoc)) van hanh tai cuc tre*.