Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dan cua » dan ca, ban cua, dai cua
mat cua » ma cua, manh cua, mang cua
cac toc » cac toi, cac nuoc, cac thoi
qua cac » cua cac
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
toc ta » toc tay, toc thai
ta van » tan van, tap van, va van

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)) ky lang xa hoi. hieu qua cac toc ta van ((mat cua) OR (dan cua)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ky lang xa hoi. hieu qua cac toc ta van ((mat cua) or (dan cua)) tre~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) ky lang xa hoi. hieu qua cac toc ta van ((mat cua) or (dan cua)) tre*.