Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thu nang » thi nang, thu hang, thu bang
xanh di » vanh dai, xanh tai
danh di » danh du, danh dien, danh gia
cau tre » cau tren, cau treo, cau tra
hieu va » lieu va, hieu qua
dam tu » nam tu, cam tu, tam tu
va dam » van dam, va dao, va dau
x hoi » xa hoi, o hoi, x ho

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) thu nang x hoi. hieu va dam tu va ((danh di) OR (xanh di)) cau tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) thu nang x hoi. hieu va dam tu va ((danh di) OR (xanh di)) cau tre~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) thu nang x hoi. hieu va dam tu va ((danh di) OR (xanh di)) cau tre*.