Perhaps you should try some spelling variations:
electronic resources » electronic resource, electronic devices
electronic sources » electron sources, electronic resource, electron source
3.2 apache » 2.2 apache, 3.6 apache, 3.2.4 apache
3 apache » _ apache, 1 apache, 5 apache
4 apache » _ apache, 1 apache, 5 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 %((electronic sources) OR (electronic resources)) %((3.2 apache) OR (((3 apache) OR (4 apache)))) software foundation%29%22.
• Adding a wildcard symbol may retrieve word variants: %22spark %((electronic sources) or (electronic resources)) %((3.2 apache) or (((3 apache) or (4 apache)))) software foundation%29%22*.