Perhaps you should try some spelling variations:
hoang van » hang va
van hanh » van thanh, ban hanh, van anh
sang ky » sang kyo, dang ky, bang ky
duc van » duc va, duc tan, duc manh
cam duc » cam xuc, cao duc, pham duc
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
tang ky » dang ky, trong ky, tang khu
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao
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: tu ((sang ky) or (tang ky)) ((lang xa) or (hoang van)) hoi. hieu va cam duc van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sang ky) OR (tang ky)) ((lang xa) OR (hoang van)) hoi. hieu va cam duc van hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sang ky) or (tang ky)) ((lang xa) or (hoang van)) hoi. hieu va cam duc van hanh vi cua tre*.