Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
van thanh » van tuan
tu sach » thu sach, te sach, tu cach
hoi cua » hoi chuc
qua cac » cua cac
cac duc » cac du, cao duc, cac dac
nang xa » nang x, lang xa, nang ma
lo nang » ho nang, ly nang, loai nang
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet

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) or (su sach)) lo nang xa hoi. hieu qua cac duc ((van thanh) OR (ban thanh)) hoi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) lo nang xa hoi. hieu qua cac duc ((van thanh) OR (ban thanh)) hoi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) lo nang xa hoi. hieu qua cac duc ((van thanh) OR (ban thanh)) hoi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) lo nang xa hoi. hieu qua cac duc ((van thanh) OR (ban thanh)) hoi cua tre*.