Perhaps you should try some spelling variations:
van khanh » van thanh, van hanh, van anh
xuc van » duc van, luc van, vuc van
thai cu » thai cua, thai xu, than cua
cac xuc » cam xuc, cac nuoc, chat xuc
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
thi cu » thi cuc
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 cac ky nang ((o hoi) or (o hai)). hieu ve cac xuc van khanh ((thai cu) OR (thi cu)) tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu cac ky nang ((o hoi) OR (o hai)). hieu ve cac xuc van khanh ((thai cu) OR (thi cu)) tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cac ky nang ((o hoi) or (o hai)). hieu ve cac xuc van khanh ((thai cu) OR (thi cu)) tren".
• Adding a wildcard symbol may retrieve word variants: tu cac ky nang ((o hoi) or (o hai)). hieu ve cac xuc van khanh ((thai cu) OR (thi cu)) tren*.