Perhaps you should try some spelling variations:
te sach » toc sach
sach ky » sac ky, sach y, sach ty
dat cua » dai cua, day cua, mat cua
vat cua » mat cua, bat cua, hat cua
qua cac » cua cac
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
toc va » hoc va, tuc va, loc va
toc ta » toc tay, toc thai

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