This depends. Taking academic materials can be stealing, unless you have a specific need to have it AND unless you go through official channels.
There are many materials that are free to access - these will generally be posted on the internet through a university site or on a public, government funded service. You can get access legitimately through many university and library settings, since such institutions pay for access to them for educational settings.
If you get these materials through a legitimate academic source such as a library or university, then it isn’t stealing because the institution has paid for access, and as a student, representative, or faculty you may use it. If you are getting it through a “pirate” site like pirate bay or something, then it is probably stealing.