The "Exclude MEDLINE records" limiter will omit any CINAHL database search results that do contain a unique PubMED ID (PMID). There are some exceptions to this limiter noted below.
- When CINAHL and MEDLINE databases index the same journal, CINAHL products may include records from particular issues that MEDLINE has chosen not to index. Therefore, although this title is covered in MEDLINE, the record will not have a PMID and thus cannot be excluded by the limiter.
- There are sometimes indexing differences between CINAHL and MEDLINE databases, such that there is not a one-to-one correspondence between records in CINAHL products and MEDLINE products. Therefore, in these cases there may not be a PMID for the CINAHL record.
PMIDs are regularly added to CINAHL records to enable the "Exclude MEDLINE records" limiter to remove MEDLINE records from search results.