Perhaps you should try some spelling variations:
irrigation requirements » irrigation equipment, nutrition requirements
requirements patents » requirements patterns, requirements papers, requirements water
functions euler » functions error, functions e.l, functions ecole
functions egfr » functions esf, functions error, functions e.l
gives » given, give

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

• If you are trying to use Boolean operators, they must be ALL CAPS: irrigation requirements patents ((functions e) OR (((functions egfr) OR (functions euler)))) gives~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "irrigation requirements patents ((functions e) or (((functions egfr) OR (functions euler)))) gives~".
• Adding a wildcard symbol may retrieve word variants: irrigation requirements patents ((functions e) or (((functions egfr) OR (functions euler)))) gives*.