Where can I find complete aircraft blueprints for the purpose of study?
You might buy some kit builder plans, as they have generally more detail than I have seen in commercially available aircraft.

With commercially available aircraft, I have bought several aircraft new, and despite pre-purchase attempts, have been unable to shake loose a complete set of prints.  Even the limited prints I was able to receive were essentially licensed, and NDA agreements were executed, copies had to be accounted for, etc.

You might be able to find prints from one of the better plan developer, which might meet your needs.  Some might be rather inexpensive.  I have plans for the Varieze and LongEz and have seem plans for other aircraft. Some are more detailed than others.

However, I would like to set an expectation that you will learn little about aircraft design, and perhaps a tiny bit about aircraft manufacturer.  There are better materials, including textbooks.