Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
ky lang » ky nang, ky dang, tay lang
ky tang » ky nang, ky dang, kho tang
xuc van » luc van, vuc van, xuc ban
duc van » duc va, duc tan, duc manh
cua tre » cua te, cuu tre, cua triet
tu ban » thu ban, te ban
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 ban ((ky lang) or (ky tang)) xa hoi. hieu vien bach ((xuc van) OR (duc van)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ban ((ky lang) OR (ky tang)) xa hoi. hieu vien bach ((xuc van) OR (duc van)) hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ban ((ky lang) or (ky tang)) xa hoi. hieu vien bach ((xuc van) OR (duc van)) hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ban ((ky lang) or (ky tang)) xa hoi. hieu vien bach ((xuc van) OR (duc van)) hanh vi cua tre*.