Perhaps you should try some spelling variations:
communication concepts » communication circuits, communication congresses, communication channels
sources divisions » resources division, course divisions, sources vision
concepts sources » concepts series
scale spaces » scale space, sample spaces
tuple spaces » tuple space, type spaces, triple space
use spaces » phase spaces, gauge spaces, whose spaces

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

• Performing a fuzzy search may retrieve terms with similar spellings: communication concepts sources divisions ((((use spaces) or (scale spaces))) or (tuple spaces))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: communication concepts sources divisions ((((use spaces) OR (scale spaces))) OR (tuple spaces)).
• Adding a wildcard symbol may retrieve word variants: communication concepts sources divisions ((((use spaces) or (scale spaces))) or (tuple spaces))*.