The following databases provide access to journal articles from many disciplines. I recommend trying out these databases first. See what comes up and then change your search tactics accordingly.
The following databases are very specific to certain subjects. Once you have an idea of your paper topic, try searching in these databases but if you don't find what you are looking for, don't fret! Try the broader databases as well (see above).
If you need high quality images for your papers, be sure to cite where you took your image from. Some reputable places to do so are the following databases, indexes, and reputable websites: