86de5828_User_Tips__SERP_URL_Parameters__Description
[URL Parameter] filter [Format Example] http://google.com/search?q=cheese&filter=0 [Description] 
Include back into the results the listings that Google omitted because they looked too similar to the ones already displayed. This is equivalent to clicking the link that says “repeat the search with the omitted results included” that you’ll often see on the last page of SERPs.
Google Power User Tips: SERP URL Parameters
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