Perhaps you should try some spelling variations:
"factores biologicos" » "factores psicologicos", "factores economicos"
"factores politicos" » "actos politicos", "valores politicos", "factores climaticos", "factos politicos", "fvalores politicos"
"actores politicos" » "actos politicos", "valores politicos"
"factores criticos" » "factores critico", "factores critica", "factores critical"

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: (((("factores politicos") OR ("factores biologicos"))) or ((("actores politicos") or ("factores criticos"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("factores politicos") OR ("factores biologicos"))) OR ((("actores politicos") OR ("factores criticos")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"factores politicos\") OR (\"factores biologicos\"))) or (((\"actores politicos\") or (\"factores criticos\"))))".
• Removing quotes may allow a broader search: (((( factores politicos ) OR ( factores biologicos ))) or ((( actores politicos ) or ( factores criticos )))).
• Adding a wildcard symbol may retrieve word variants: (((("factores politicos") OR ("factores biologicos"))) or ((("actores politicos") or ("factores criticos"))))*.