Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
ty mang » ty hang, tin mang, tri mang
hieu vu » hieu va, hieu su, dieu vu
hieu ve » hieu va, hieu van
soc van » hoc van, oc van, sac van
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: tu sach ((ty mang) OR (ty xang)) xa hoi. ((hieu vu) or (hieu ve)) cham soc van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty mang) OR (ty xang)) xa hoi. ((hieu vu) OR (hieu ve)) cham soc van hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty mang) OR (ty xang)) xa hoi. ((hieu vu) or (hieu ve)) cham soc van hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty mang) OR (ty xang)) xa hoi. ((hieu vu) or (hieu ve)) cham soc van hanh vi cua tre*.