Perhaps you should try some spelling variations:
integration theorems » integration theories, integration theory, integrationstheorie 2
irrigation scheme » irrigation systems
trip irrigation » drip irrigation, crop irrigation, grain irrigation
supply grid » supply crowd, supply great, support grid
supply trip » supply tariff, supply trade

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 theorems. ) or ( supply trip irrigation scheme. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( supply grid integration theorems. ) OR ( supply trip irrigation scheme. )).
• Adding a wildcard symbol may retrieve word variants: (( supply grid integration theorems. ) or ( supply trip irrigation scheme. ))*.