Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van thai » van thoai, van tai, van hai
thai lon » thai long, thai son, thai loi
ky lang » ky nang, ky tang, tay lang
ky dang » ky nang, ky danh
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
te cac » ve cac, te cao, de 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: ((te cac) or (tu cac)) ((ky lang) OR (ky dang)) xa hoi. hieu van thai lon va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te cac) OR (tu cac)) ((ky lang) OR (ky dang)) xa hoi. hieu van thai lon va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te cac) or (tu cac)) ((ky lang) OR (ky dang)) xa hoi. hieu van thai lon va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te cac) or (tu cac)) ((ky lang) OR (ky dang)) xa hoi. hieu van thai lon va hanh vi cua tre*.