The International Music Score Library Project (Petrucci Library) is an online collection of scores that are in the public domain. It has 74,000 works included, making it an excellent score source. This means that it is strongest in compositions written before 1923, so most 20th/21st century will not be included, unless the composer has given permission for it to be made available. Also, these may not always be the most authoritative edition, so you may also want to consult a more critical edition held by the library.
Print scores at Van Wylen are housed on the 2nd floor and can be located by searching in HopeCat. You can search just for scores by starting in the Advanced Search and limiting the Material Type to "Music Score."
Scores can be somewhat tricky to find because of the variation in what works are named. Here are a few tips to help locate them.
Start your search in HopeCat Advanced search with the composer name and a couple of words from the title of the work:
In the results, if you find your piece, you can use the information provided in the record to make sure you are seeing all of the possible editions. Underneath the publication information, look in the Subject area for the title of your piece. This particular formating of the title is called the Uniform Title and it is attached to every edition of this particular piece that we have. You can follow the linked title to see all of the editions of this work that we have.