Perhaps you should try some spelling variations:
innovation sources » information sources, innovation surveys, innovation policies
social innovation » social isolation, social integration, social interaction
data transmission » gas transmission, _ transmission, hiv transmission
essential social » essential oils, essential skills
lines » line

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( essential social innovation sources ) or ( _ data transmission lines ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( essential social innovation sources ) OR ( _ data transmission lines )).
• Adding a wildcard symbol may retrieve word variants: (( essential social innovation sources ) or ( _ data transmission lines ))*.