Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thu sach » thuat sach, thuoc sach, thu hoach
thanh de » hanh de, thanh ve, thanh do
hoc dua » hoc duc, hoc lua, hoc du
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
tu sach » su sach, te sach, tu cach
xang x » nang x
de cua » le cua, te cua, dieu cua
x hoi » xa hoi, o hoi, x ho

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) OR (tu sach)) ty xang x hoi. hieu va ((hoc dua) or (hoc cua)) van thanh de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) ty xang x hoi. hieu va ((hoc dua) OR (hoc cua)) van thanh de cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) OR (tu sach)) ty xang x hoi. hieu va ((hoc dua) or (hoc cua)) van thanh de cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) OR (tu sach)) ty xang x hoi. hieu va ((hoc dua) or (hoc cua)) van thanh de cua tre*.