Perhaps you should try some spelling variations:
so sanh » do sanh
sanh ky » hanh ky, sang ky, nganh ky
hieu ve » hieu va, hieu van
cac tuc » cac toc, cac tu, cac tac
tuc cac » tu cac, tich cac
co hoi » co hoc, co loi
ve cac » va cac, vien cac
va cua » va chua, via cua, ma cua
ca cua » co cua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: so sanh ky nang ((cau hoi) or (co hoi)). hieu ve cac tuc cac dan ((va cua) or (ca cua)) tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sanh ky nang ((cau hoi) OR (co hoi)). hieu ve cac tuc cac dan ((va cua) OR (ca cua)) tu.
• Adding a wildcard symbol may retrieve word variants: so sanh ky nang ((cau hoi) or (co hoi)). hieu ve cac tuc cac dan ((va cua) or (ca cua)) tu*.