Perhaps you should try some spelling variations:
van phan » van phong, van thanh, luan phan
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
van hai » van ha, van chat
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: su sach ky nang xa hoi. hieu ((van hai) OR (van phan)) trac ((ban hanh) or (van hanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang xa hoi. hieu ((van hai) OR (van phan)) trac ((ban hanh) OR (van hanh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang xa hoi. hieu ((van hai) OR (van phan)) trac ((ban hanh) or (van hanh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang xa hoi. hieu ((van hai) OR (van phan)) trac ((ban hanh) or (van hanh)) vi cua tre*.