Many of the library databases allow searches for reviews in addition to scholarly articles. Often you can limit your search by using the document type "review". Combine this with a search using the movie title, and this should retrieve film reviews. It is helpful to know the film's release date since most reviews are published after the release.
Film Review Annual
PN 1995 .F463 DBW reference
Film Review Index
Z 5784 .M9F513 DBW reference
The New York Times Film Reviews
PN 1995 .N4 DBW reference
Variety Film Reviews
PN 1995 .V34 DBW reference
Retrospective Index to Film Periodicals, 1930-1971
Z5784.M9B39 DBW reference
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