Hi Lisa,
Take a look at thesauri/taxonomies used in Medline Plus and PubMed. The one well-known is MeSH (Medical Subject Headings). The selection of a thesaurus depends on the content, target audience, and the function of your digital repository. You can create a thesaurus from your corpus or adapt an existing thesaurus/controlled vocabulary.
Hopefully it helps.
Best,
Joan
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Joan Wang
East Asian/Chinese Studies Librarian
Washington University in Saint Louis
She/Her/Hers
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