Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
va danh » va dinh, va dan, va hanh
cac bac » cac bai, cac ban, cac cach
sang ky » sang kyo, tang ky, bang ky
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
dang ky » dang y, dan ky, dong ky
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac
vi cua » vai cua, di 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 ((sang ky) OR (dang ky)) lang xa hoi. hieu ve cac bac ((va danh) or (van hanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sang ky) OR (dang ky)) lang xa hoi. hieu ve cac bac ((va danh) OR (van hanh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((sang ky) OR (dang ky)) lang xa hoi. hieu ve cac bac ((va danh) or (van hanh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: so ((sang ky) OR (dang ky)) lang xa hoi. hieu ve cac bac ((va danh) or (van hanh)) vi cua tre*.