Perhaps you should try some spelling variations:
khanh thai » nhanh thai, khanh thanh, khanh thuan
van khanh » van thanh, van hanh, van anh
cu tren » tu tren, dua tren
thai cu » thai cua, thai xu, thi cu
luc van » luoc van, luu van, duc van
ve cac » va cac, vien cac
ve cau » ke cau, va cau, le cau
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 cau) OR (ve cac)) luc van khanh thai 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 cau) OR (ve cac)) luc van khanh thai 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 cau) OR (ve cac)) luc van khanh thai cu tren".
• Adding a wildcard symbol may retrieve word variants: tu cac ky nang ((o hoi) or (o hai)). hieu ((ve cau) OR (ve cac)) luc van khanh thai cu tren*.