Perhaps you should try some spelling variations:
"support crop irrigation system." » "support crop irrigation systems.", "support crop irrigation water.", "support crop irrigation scheme.", "support scale irrigation system.", "support canal irrigation system.", "support large irrigation system.", "support crops irrigation system.", "support cross irrigation system.", "support across irrigation system."
"support drip irrigation system." » "support drip irrigation systems.", "support drip irrigation water.", "support drip irrigation scheme.", "support deep irrigation system.", "support during irrigation system.", "support crops 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 crop irrigation system.") OR ("support drip irrigation system."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"support crop irrigation system.\") OR (\"support drip irrigation system.\"))".
• Removing quotes may allow a broader search: (( support crop irrigation system. ) OR ( support drip irrigation system. )).
• Adding a wildcard symbol may retrieve word variants: (("support crop irrigation system.") OR ("support drip irrigation system."))*.