Perhaps you should try some spelling variations:
"maternal nutrition" » "materna nutrition", "materials nutrition", "maternal nutricion"
"external nutrition" » "external nutricion"
"material nutrition" » "material nutricion"
"internal nutritivo" » "integral nutritivo", "internet nutritivo"

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((((((\"maternal nutrition\") OR (\"external nutrition\"))) OR (\"internal nutritivo\"))) OR (((\"material nutrition\") OR (\"materia nutritiva\"))))~".
• Removing quotes may allow a broader search: (((((( maternal nutrition ) OR ( external nutrition ))) OR ( internal nutritivo ))) OR ((( material nutrition ) OR ( materia nutritiva ))))~.
• Adding a wildcard symbol may retrieve word variants: (((((("maternal nutrition") OR ("external nutrition"))) OR ("internal nutritivo"))) OR ((("material nutrition") OR ("materia nutritiva"))))*.