Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh tri » thanh tri, hanh tai, hanh trinh
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
cam vuc » cam xuc
vuc van » duc van, luc van, thuc van
cua tre » cua te, cuu tre, cua triet
y song » c song, k song, hay song
_ song » _ son, c song, k song

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 ((y song) OR (_ song)) xa hoi. ((hieu ve) or (hieu qua)) cam vuc van hanh tri cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y song) OR (_ song)) xa hoi. ((hieu ve) OR (hieu qua)) cam vuc van hanh tri cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((y song) OR (_ song)) xa hoi. ((hieu ve) or (hieu qua)) cam vuc van hanh tri cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((y song) OR (_ song)) xa hoi. ((hieu ve) or (hieu qua)) cam vuc van hanh tri cua tre*.