Perhaps you should try some spelling variations:
thanh doi » thanh loi, thanh moi, thanh do
ban thanh » ban hanh, ban hang
tu sach » thu sach, su sach, te sach
cau hoc » cau hoi, cau hoa, cao hoc
doi cua » dai cua, hoi cua
cau loc » hau loc, cau luc, cau long
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
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 ky nang xa hoi. ((hieu ve) or (lieu va)) ((cau loc) OR (cau hoc)) ban thanh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. ((hieu ve) OR (lieu va)) ((cau loc) OR (cau hoc)) ban thanh doi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang xa hoi. ((hieu ve) or (lieu va)) ((cau loc) OR (cau hoc)) ban thanh doi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. ((hieu ve) or (lieu va)) ((cau loc) OR (cau hoc)) ban thanh doi cua tre*.