Use Google Reading Level settings to help narrow your search. The levels aren't necessarily associated to grade levels or Lexile scores, but it's a start.
For example you may want to search for Lewis and Clark, which will return results similar to these listed below.
Find the Advanced Search button (gear shift icon in upper right).
Out of the Advanced Search options find Reading Level and make your selection.
The new results will have Reading Level breakdowns listed by percentages. From here click on Basic, Intermediate, Advanced, or "All" to see particular selections of interest.
Remember, be more descriptive in your searches by adding additional keywords to narrow your search. For example when I search for Lewis and Clark, do I mean explorers, or the college? The additional keywords will be very helpful.
