NOTE:
Most of your searches will only yield under a dozen results.
That is a Good thing! The reason we use subject databases is to help filter the superfluous content.
Example:
If I'm interested in using Pehr Kalm, Travels in North America, 1770 as a historic document, I can search ("pehr kalm" OR "peter kalm") and nothing else in America: History and Life for ~13 history-related results. Compare this to results from PRIMO, JSTOR, and GoogleScholar
EXAMPLES:
If you're really stuck, another option is to search the title of the document itself in JSTOR and see what other scholars have written about the material.
Example: Mittelberger AND "Journey to Pennsylvania"