Perhaps you should try some spelling variations:
integration theory » integration through, information theory, integration report
grid integration » trade integration, _ integration, data integration
rating services » heating services, trading services, making services
supply grid » supply crowd, support grid
from rating » from reacting, from latin, from floating

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( supply grid integration theory. ) or ( support from rating services. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( supply grid integration theory. ) OR ( support from rating services. )).
• Adding a wildcard symbol may retrieve word variants: (( supply grid integration theory. ) or ( support from rating services. ))*.