Perhaps you should try some spelling variations:
"autoregressive with exogenous impacts" » "autoregressive with exogenous inputs"
"autoregressive with exogenic impacts" » "autoregressive with biogenic impact", "autoregressive with zoogenic impact", "autoregressive with economic impacts"
"autoregressive with exogenous input" » "autoregressive with exogenous inputs", "autoregressive with endogenous input", "autoregressive with exogenous insulin"

Try widening your search to All Fields.

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: (("autoregressive with exogenous input") OR ((("autoregressive with exogenous impacts") OR ("autoregressive with exogenic impacts")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"autoregressive with exogenous input\") or (((\"autoregressive with exogenous impacts\") OR (\"autoregressive with exogenic impacts\"))))".
• Removing quotes may allow a broader search: (( autoregressive with exogenous input ) or ((( autoregressive with exogenous impacts ) OR ( autoregressive with exogenic impacts )))).
• Adding a wildcard symbol may retrieve word variants: (("autoregressive with exogenous input") or ((("autoregressive with exogenous impacts") OR ("autoregressive with exogenic impacts"))))*.