Perhaps you should try some spelling variations:
computer programs » computer program (Expand search)
maize pathogen » maize nitrogen (Expand search), main pathogens (Expand search)
using coupling » running coupling (Expand search), using competing (Expand search), using coupled (Expand search)
pathogen and » pathogens and (Expand search), pathogenic and (Expand search), pathogen in (Expand search)
and computer » _ computer (Expand search)

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: (( maize pathogen AND computer programs ) OR ( using coupling _ python programming ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( maize pathogen and computer programs ) OR ( using coupling _ python programming ))~".
• Adding a wildcard symbol may retrieve word variants: (( maize pathogen and computer programs ) OR ( using coupling _ python programming ))*.