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