Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
sanh ky » hanh ky, nganh ky, thanh ky
va hanh » va thanh, va danh, ban hanh
hieu ve » hieu va, hieu van
dang ma » dang mau, dang mam, dang mat
sang ky » sang kyo, dang ky, tang ky
voi hoa » voi hoat, voi khoa, boi hoa
ma hoi » mai hoi, xa hoi, ma hoa
ve nam » he nam, va nam, le nam

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) or (sang ky)) dang ma hoi. hieu ve nam thu ((va hanh) OR (van hanh)) voi hoa viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sanh ky) OR (sang ky)) dang ma hoi. hieu ve nam thu ((va hanh) OR (van hanh)) voi hoa viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((sanh ky) or (sang ky)) dang ma hoi. hieu ve nam thu ((va hanh) OR (van hanh)) voi hoa viet".
• Adding a wildcard symbol may retrieve word variants: so ((sanh ky) or (sang ky)) dang ma hoi. hieu ve nam thu ((va hanh) OR (van hanh)) voi hoa viet*.