Perhaps you should try some spelling variations:
thuc ban » thuoc ban, thu ban, thuc van
thuc dan » thuc hanh, hoc dan, thuc vat
so sach » so sanh, bo sach, co sach
vang xa » lang xa, mang xa, ang xa
hieu ve » hieu va, hieu van
y vang » ly vang
ve nam » he nam, va nam, le nam
di cua » doi cua, de cua, do cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y vang xa hoi. hieu ve nam ((thuc ban) OR (thuc dan)) hanh ((di cua) or (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y vang xa hoi. hieu ve nam ((thuc ban) OR (thuc dan)) hanh ((di cua) OR (dai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y vang xa hoi. hieu ve nam ((thuc ban) OR (thuc dan)) hanh ((di cua) or (dai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: so sach y vang xa hoi. hieu ve nam ((thuc ban) OR (thuc dan)) hanh ((di cua) or (dai cua)) tre*.