Perhaps you should try some spelling variations:
"support cross irrigation systems." » "support crop irrigation systems.", "support from irrigation systems.", "support cross correlation systems.", "support across irrigation systems.", "support crops irrigation systems.", "support come irrigation systems.", "support cross irrigation system."
"export cross irrigation systems." » "export crop irrigation systems.", "export from irrigation systems.", "export cross correlation systems.", "export crops irrigation systems.", "exports across irrigation systems.", "export costs irrigation systems.", "export cross irrigation system."

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("support cross irrigation systems.") OR ("export cross irrigation systems."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"support cross irrigation systems.\") OR (\"export cross irrigation systems.\"))".
• Removing quotes may allow a broader search: (( support cross irrigation systems. ) OR ( export cross irrigation systems. )).
• Adding a wildcard symbol may retrieve word variants: (("support cross irrigation systems.") OR ("export cross irrigation systems."))*.