Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
van hanh » van thanh, ban hanh, van anh
dang xay » dang van, van xay
hieu van » hieu va, thien van, lieu va
xay hoi » xa hoi, tay hoi, cay phoi
hieu ve » hieu va
tuc van » thuc van, truc van, tuc va
cam tuc » cam xuc, cam tu, nam thuc
vi cua » vai cua, di cua
cua te » cua tu
y dang » ky dang, 2 dang, _ dang

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: ((toc sach) OR (doc sach)) y dang xay hoi. ((hieu ve) OR (hieu van)) cam tuc van hanh vi cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (doc sach)) y dang xay hoi. ((hieu ve) or (hieu van)) cam tuc van hanh vi cua te~".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (doc sach)) y dang xay hoi. ((hieu ve) or (hieu van)) cam tuc van hanh vi cua te*.