Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
ky tang » ky nang, kho tang, ky trong
ky dang » ky nang, ky danh
hieu ve » hieu va, hieu van
cua tre » cuu tre, cua triet, dua tren
tu sac » tu sach, tu cac, tu san
ve cac » va cac, vien cac
du van » duy van, duc van, tu van
cua te » cua tu

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ((ky tang) OR (ky dang)) xa hoi. hieu ve cac du van hanh vi ((cua tre) OR (cua te))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ((ky tang) OR (ky dang)) xa hoi. hieu ve cac du van hanh vi ((cua tre) or (cua te))~".
• Adding a wildcard symbol may retrieve word variants: tu sac ((ky tang) OR (ky dang)) xa hoi. hieu ve cac du van hanh vi ((cua tre) or (cua te))*.