Perhaps you should try some spelling variations:
thanh di » thanh doi, thanh de, thanh do
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu ve » hieu van
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
luc va » tuc va, loc va
di cua » dai cua, doi cua, de cua

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