Perhaps you should try some spelling variations:
irrigation requirements » irrigation equipment, nutrition requirements
data presenting » data presentation
requirements a » requirements _
a imprecision » _ imprecision, a precision, data imprecision
data creating » data cleaning
data testing » data fitting, a testing, data writing

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

• Performing a fuzzy search may retrieve terms with similar spellings: irrigation requirements a imprecision ((((data presenting) or (data testing))) or (data creating))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: irrigation requirements a imprecision ((((data presenting) OR (data testing))) OR (data creating)).
• Adding a wildcard symbol may retrieve word variants: irrigation requirements a imprecision ((((data presenting) or (data testing))) or (data creating))*.