Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
nuoc van » nuoc va, nuoc san, luoc van
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
vien cac » vien bach, vien dai, vien da
cuc tre » duc tre, cua tre, cuu tre
tu san » thu san, tu ban, tu can
te ban » te bao
o hoi » co hoi, o hoc, o hoa
o hai » co hai, so hai, o lai

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) or (te ban)) ky nang ((o hoi) or (o hai)). hieu vien cac nuoc van hanh tai cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu san) OR (te ban)) ky nang ((o hoi) OR (o hai)). hieu vien cac nuoc van hanh tai cuc tre.
• Adding a wildcard symbol may retrieve word variants: ((tu san) or (te ban)) ky nang ((o hoi) or (o hai)). hieu vien cac nuoc van hanh tai cuc tre*.