Your Query returns 3 Accession Numbers:

Query TermAccessionNCBI TaxonidSynonymsPhenotype (OMIM) *
NR3A1NM_1529597955ESR    ER[a]    zfER[a]    esr1   
Nr3a1NM_00795610090ERa    ESR    Estr    ER[a]    Estra    ERalpha    Esr1   
NR3A1NM_0001259606ER    ESR    Era    ESRA    ESR1   

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

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