No,
Unfortunately no, you can export aggregate flows up until the limit [Based on number of flow/memory allocation]. Bottom of the application flow grid.
![5c5e7bf922f94482b1901065f83ae04d_RackMultipart20160711-88690-gv6uln-AggregateFlowTime_inline.png 5c5e7bf922f94482b1901065f83ae04d_RackMultipart20160711-88690-gv6uln-AggregateFlowTime_inline.png](/t5/image/serverpage/image-id/1200iCF9EC71567095F29/image-size/large?v=v2&px=999)
Purview isn't really designed for data retention for raw flow data, generally we would recommend you export it to SIEM.