Sarfend, it sounds like it is following your instructions.
Just like Google works (count yourself lucky, there are 622 million returns for "leather" on that search engine - excuse my delay in replying, I got held up viewing some of the results ...).
Just like Google works (as per Alex), add some more info (keywords) to your query to narrow it down.
As to how far back the search looks, this is pretty irrelevant, as it is by default returned newest first anyway (so unless you peruse to the end, you'll never find out what Moses used)
If it really irks you, just use the pull-down menu "Search previous:" to select your preferred date range.
One last tip: add an asterisk "*" as a wildcard to "root" words (ie wash* to search for all possible entries for wash, washed, washing ... erm washabi :? etc)