While all of the education databases listed on the general resources page will have information on project-based learning, here are two in particular that may be helpful.
Education Research Complete indexes citations, abstracts, and full text from journals, books, book chapters, case studies, essays, interviews, conference proceedings, product reviews, and experiments in all areas of education. You can limit to peer-reviewed journals. 1865-present.
The database provides indexing and abstracts for more than 2,100 journals, as well as full text for nearly 1,300 journals. This database also includes full text for nearly 550 books and monographs, full text for numerous education-related conference papers, plus author profiles for the most prolific authors in the field.
Teacher Reference Center indexes abstracts, citations, and full-text articles from academic journals, magazines, directories, biographies, and case studies on all aspects of education.The full-text materials are available in both HTML and PDF formats. You can limit to peer-reviewed sources. 1984-present.