Google Scholar is a special search engine in Google that specifically looks for research articles. If you use it from on-campus, then it will give you a link to an article if it's in one of the library databases.
WorldCat is a database that has all of the holdings from over 17,000 libraries worldwide. This is the database the library uses when you request something on interlibrary loan. If you log in from on-campus, it will even tell you if KU already has what you are looking for.
While doing research, it should be easy to find the best databases in your discipline.
All you must do is go to the Databases A-Z page at https://library.kutztown.edu/az.php (You might want to Bookmark this).
Then, at the top, you will see a drop-down menu called ALL SUBJECTS
From that menu, select the subject you need. It will then list the best databases for that subject.