Perhaps you should try some spelling variations:
28electronic resource » electronic resource, electric resource, electronic sources
electronic resources » electronic resource, electronic devices
3a apache » 3 apache, a apache, 33 apache
31 apache » 3 apache, 11 apache, 51 apache
1 apache » _ apache, 3 apache, 4 apache

Try widening your search to All Fields.

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: %22spark %((28electronic resource) OR (electronic resources)) %((((3a apache) OR (31 apache))) OR (1 apache)) software foundation%29%22.
• Adding a wildcard symbol may retrieve word variants: %22spark %((28electronic resource) or (electronic resources)) %((((3a apache) or (31 apache))) or (1 apache)) software foundation%29%22*.