Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh doi » thanh loi, thanh moi, thanh do
tu sach » thu sach, su sach, te sach
cac dac » cac dan, cac dai, cac bac
cuu tre » cau tren, cau treo
cua tre » cua te, cua triet, dua tren
sach ky » sac ky, sach y, sach ty
cac duc » cac du, cao duc, cac nuoc
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, nang ma

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