Perhaps you should try some spelling variations:
hieu ve » hieu va, hieu van
cac tuc » cac toc, cac tu, cac tac
xa hanh » xa thanh, xa khanh, va hanh
vai cua » dai cua, lai cua, bai cua
hai cua » thai cua, dai cua, hoi cua
tu can » tu ban, tu cac, thu canh
can ky » van ky, dan ky, ban ky
co hoi » co hoc, co loi
ve cac » va cac, vien cac
o hoi » o hoc, o hai, 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 can ky nang ((o hoi) OR (co hoi)). hieu ve cac tuc xa hanh ((vai cua) or (hai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu can ky nang ((o hoi) OR (co hoi)). hieu ve cac tuc xa hanh ((vai cua) OR (hai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu can ky nang ((o hoi) OR (co hoi)). hieu ve cac tuc xa hanh ((vai cua) or (hai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu can ky nang ((o hoi) OR (co hoi)). hieu ve cac tuc xa hanh ((vai cua) or (hai cua)) tre*.