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The &as_qdr parameters originate when the query comes from Advanced Search. The &tbs parameters occur when the time restrictions originate with the new Search Options [webmasterworld.com]. Looks like two different teams working on this - only partial consistency between the naming conventions.
parameter when added to the end of a Google search URL.
Some of my pages show a date at the beginning of the snippet. Suspected Supplemental Results do not.
By adding this parameter, the date changes from black typeface to grey, and the date appears for *all* entries in the SERP.
It would be nice to have a tool for researching "supplemental results" or whatever the Google Backwaters should be called these days.
In one case I see 1900 results for a straight site: search, but 2,300 for a "recent" site: search. Or the case I mentioned above, the change goes the other direction (more expected): 119 "straight" site: operator results but only 13 "recent" results.
I was hanging out for this - you can now look for things in the month of July 2007, for example.
Not sure if it works outside of Groups Search though.
Title, snippet, cache, are all independant, updated at different times, and what you 'see' for those might not be the same as what is being considered for ranking that 'page'.