Perhaps you should try some spelling variations:
communication concepts » communication circuits, communication congresses, communication channels
based extension » based extraction
concepts based » concept based, concepts cases, concepts case
range spaces » range states, large spaces, tangent spaces
gauge spaces » safe spaces, use spaces
large space » large sparse, large scale, large surface

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 based extension ((((range spaces) or (gauge spaces))) or (large space))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: communication concepts based extension ((((range spaces) OR (gauge spaces))) OR (large space)).
• Adding a wildcard symbol may retrieve word variants: communication concepts based extension ((((range spaces) or (gauge spaces))) or (large space))*.