The GT Library has 260+ databases. All databases are accessible through the "Find Articles (Databases)" Page.
Here's a quick non-comprehensive list of some commonly used databases to start an aerospace literature search.
USEFUL PROFESSIONAL SOCIETY DATABASES:
ARC (AIAA) - Includes journals, conferences, and e-books of the American Institute of Aeronautics and Astronautics.
IEEE - Transaction, journals, and conference papers of the Institute of Electrical and Electronics Engineers.
ASME - Journals and conference papers of the American Society of Mechanical Engineers.
OSA - Journals and conference papers of the Optical Society of America
SPIE - Journals and conference papers of this professional society for optics and photonics technology.
USEFUL AEROSPACE ENGINEERING DATABASES:
Aerospace Database (ProQuest) - searches a wide swath of literature from most professional academic literature relevant to Aerospace Engineering.
Compendex - Comprehensive engineering database, covers academic literature in all engineering sub-disciplines, including AE.
Web of Science - Robust, interdisiciplinary, and authoritiative database of all scientific and engineering research fields.