These are our two main history databases. Each one indexes articles from thousands of history journals and magazines. While journal articles are the focus, you may also find citations for dissertations, conference papers, and book chapters. These databases should be your starting point for history research, because they combine a focus on history with coverage of a very broad range of journals.
JSTOR is actually a journal repository. Every journal in JSTOR has 100% full text, but a journal only appears in JSTOR at all if the publisher has made and agreement with the repository. So, there are only about 400 total history journals in JSTOR, while America: History and Life indexes from 1800 journals. This difference in breadth of coverage is why the two databases above should be your starting point for research, not JSTOR.
But where JSTOR shines is that you can search the full text of every article in there. Trying to research an event, place, or person that is rarely featured in articles? Go to JSTOR and find every single article that mentions that person or thing even a single time!
Library search is also not really a database-- it is a tool that cross searches databases, plus our library catalog. It usually isn't a good starting point for history research, because the large numbers of results can be messy and hard to sort through. It's strength is when you want to go beyond what is published in the history scholarship to look at sources published in other disciplines.
Using Limiters in Historical Abstract and America: History and Life
Using Advanced Search with Boolean Searching
An introduction to narrowing searches in JSTOR and also using to find both primary and secondary sources.