Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
su triet » su viet, su tien, ve triet
quang xa » quang ma, quang va, quang xuan
quan xa » quan ha, quan va, quan cua
hieu va » lieu va, hieu qua
danh vi » hanh vi, dinh vi, danh di
sach x » sach xa, sach xu, sach y
loc va » hoc va, luc va
tuc va » thuc va, truc va, tuc xa
vi su » va su, ve su, ki su

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 x ((quang xa) OR (quan xa)) hoi. hieu va cac ((loc va) OR (tuc va)) danh vi su triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach x ((quang xa) OR (quan xa)) hoi. hieu va cac ((loc va) or (tuc va)) danh vi su triet~".
• Adding a wildcard symbol may retrieve word variants: toc sach x ((quang xa) OR (quan xa)) hoi. hieu va cac ((loc va) or (tuc va)) danh vi su triet*.