Reviews of musical performances can be found in many places. For performances from recent decades you may have more luck with online resources. For older performances, especially of major classical composers, you may need to look in books. The internet can be a great source of reviews... except when it's not. In all cases, if one resource yields meager results, try another one.
Below are some suggestions for finding reviews in various library databases. Unfortunately, they don't always work as advertised. If you don't find sufficient results using the given limits and search settings, just try a general keyword search. Everything depends on how the material has (or has not) been indexed by the database's creators.
Sometimes books about composers or individual compositions contain excerpts from significant performance reviews. When searching the library catalog, select SUBJECT HEADING BROWSE in the "within" box and enter the name of your composer (last name, first name). Look for sub-headings like "history and criticism," or the title of the composition you're researching.
Another possibility is to enter "first performances" in the search box. This will lead you to books that discuss the first performances of selected works.
Still another approach is to search for the subject term "musical criticism"