Perhaps you should try some spelling variations:
integration schemes » integration schengen, integration regimes, integration some
surface irrigation » scale irrigation
irrigation schemes » irrigation scheme, irrigation systems
upper surface » summer surface, other surface, der surface
support grid » support agri, support grant, support group

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

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