Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
viet qua » vien quan, ket qua, viet ha
viet cua » viec cua, viet ca, biet cua
tan dinh » tran dinh, van dinh, tai dinh
sach thu » sach thue, sach thieu, sach tham
cac duc » cac du, cao duc, cac dac
hieu ve » hieu va, hieu van
xang xa » lang xa, mang xa, dang xay
ve cac » va cac, vien cac
ang xa » lang xa, mang xa, dang xay

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach thu ((xang xa) OR (ang xa)) hoi. hieu ve cac duc tan dinh ((viet cua) or (viet qua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach thu ((xang xa) OR (ang xa)) hoi. hieu ve cac duc tan dinh ((viet cua) OR (viet qua)) tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach thu ((xang xa) OR (ang xa)) hoi. hieu ve cac duc tan dinh ((viet cua) or (viet qua)) tre*".