Many websites exist to catalog Academic History Journals. The best known of these websites is JSTOR. However, JSTOR is a paid membership though if you have a university affiliated email, you'll likely bee able to view and download sources. If you don't have a paid membership, you can use their open access site here.
Another great idea would be to search individual university libraries. For example, I have an interest in Irish American History, and was able to find open archives at Villanova, NYU, and Indiana University that had digitized their primary sources on Irish America. These were all available for free and most were available without sing-up! If you want to go down this route I would try and figure out Universities that have leading department on the history of education in the United States and begin checking their libraries, then google "[University Name] Digital Archives" or "[University Name] Digital Collections"
Finally, the Federal and Stat Government agencies often have large digital collections. For example NY States' DoE. To find these google "[Agency Name] Digital Archives" or "[Agency Name] Digital Collections."
Research can be really tedious, but the key is to stick to it. If you find a topic interesting, odds are there are thousands of people who also find it interesting, and at least some of them have helped centralize a collection of primary and secondary sources. Good Luck!!!