Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
cac duc » cao duc, cac dac, cac nuoc
cua tre » cuu tre, cua triet, dua tren
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: su sach ty nang xa hoi. hieu qua ((cac duc) OR (cac du)) van hanh vi ((cua tre) OR (cua te))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty nang xa hoi. hieu qua ((cac duc) OR (cac du)) van hanh vi ((cua tre) or (cua te))~".
• Adding a wildcard symbol may retrieve word variants: su sach ty nang xa hoi. hieu qua ((cac duc) OR (cac du)) van hanh vi ((cua tre) or (cua te))*.