Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
dang xay » dang van, van xay
hang di » hang doi, hang vi, hang dien
hanh de » hanh ve, hanh kem
cac dac » cac dan, cac dai, cac bac
hieu va » lieu va, hieu qua
lang xa » lang ha, lang van
sach v » sach va, sach y, sach 2
dac va » duc va, day va, dat va
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach v ((lang xa) OR (dang xay)) hoi. hieu va cac dac va ((hanh de) or (hang di)) cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach v ((lang xa) OR (dang xay)) hoi. hieu va cac dac va ((hanh de) OR (hang di)) cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach v ((lang xa) OR (dang xay)) hoi. hieu va cac dac va ((hanh de) or (hang di)) cua te".
• Adding a wildcard symbol may retrieve word variants: hoc sach v ((lang xa) OR (dang xay)) hoi. hieu va cac dac va ((hanh de) or (hang di)) cua te*.