Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
so sanh » do sanh
ky lang » ky dang, ky tang, tay lang
hieu ve » hieu va
cac duc » cac du, cao duc, cac dac
duc van » duc va, duc tan, duc manh
cua tre » cua te, cuu tre, cua triet
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 sanh ((ky lang) OR (ky nang)) xa hoi. ((hieu ve) OR (hieu van)) cac duc van hanh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sanh ((ky lang) OR (ky nang)) xa hoi. ((hieu ve) OR (hieu van)) cac duc van hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: so sanh ((ky lang) OR (ky nang)) xa hoi. ((hieu ve) OR (hieu van)) cac duc van hanh vi cua tre*.