Your Query returns 7 Accession Numbers:

Query TermAccessionNCBI TaxonidSynonymsPhenotype (OMIM) *
Pghs1NM_00896910090COX1    Cox-1    Cox-3    Ptgs1    176805
PGHS1BC0298409606PGHS-1    PGG/HS    COX1    PTGHS    COX3    PCOX1    PHS1    PTGS1    176805
PGHS1NM_0009629606COX1    COX3    PHS1    PCOX1    PTGHS    PGG/HS    PGHS-1    PTGS1    176805
PGHS1NM_0805919606COX1    COX3    PHS1    PCOX1    PTGHS    PGG/HS    PGHS-1    PTGS1    176805
Pghs1BC00557310090COX1    Cox-1    Ptgs1    176805
Pghs1BC02332210090COX1    Cox-1    Ptgs1    176805
Pghs1NC_004757228410COX1    Cox-1    Ptgs1   

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* OMIM link based on symbol match for human and mouse.

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Text2Knowledge ... Yong Huang 2002