Getting the most out of a scholarly subject-based (education) database like ERIC means using an advanced search.
Type in your subject/topic then scroll down to the bottom of the Advanced Search screen and select:
Primary Search database above offers content appropriate for various levels of primary education (K-7th grade). Use "Lexile Reading Level" and select 300-500 (for 3rd to 5th grade materials).
Use this link if you would like to find additional databases by subject area.