Perhaps you should try some spelling variations:
khoa tang » khoa dang, khoa tieng, khoa trung
van hanh » van thanh, ban hanh, van anh
kho tang » cao tang
chat luc » chat xuc, chat lua, nhan luc
luc van » luoc van, luu van, duc van
hieu va » lieu va
cua tre » cua te, cuu tre, cua triet
ha hoi » hoa hoi, ha noi, xa hoi
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 tai ((khoa tang) OR (kho tang)) ha hoi. ((hieu va) or (hieu qua)) chat luc van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu tai ((khoa tang) OR (kho tang)) ha hoi. ((hieu va) OR (hieu qua)) chat luc van hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu tai ((khoa tang) OR (kho tang)) ha hoi. ((hieu va) or (hieu qua)) chat luc van hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu tai ((khoa tang) OR (kho tang)) ha hoi. ((hieu va) or (hieu qua)) chat luc van hanh vi cua tre*.