Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thu nang » thi nang, thu hang, thu bang
van dinh » van minh, van dich, va dinh
dinh di » dinh du, dinh vi, danh di
cuu tre » cua tre, cau tren, cau treo
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
cam tu » cam thu, dam tu, tam tu
nam tu » nam thu, nam thuc
di cuu » di cau, di cua, dinh cuu

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 xa hoi. hieu va ((cam tu) OR (nam tu)) van dinh di cuu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) thu nang xa hoi. hieu va ((cam tu) or (nam tu)) van dinh di cuu tre~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) thu nang xa hoi. hieu va ((cam tu) or (nam tu)) van dinh di cuu tre*.