How to find the number of full table scans

From the Oracle Documentation:

The view DBA_HIST_SEG_STAT view displays historical information about segment-level statistics. This view captures the top segments based on a set of criteria and captures information from V$SEGSTAT. The total value is the value of the statistics since instance startup. The delta value is the value of the statistics from the BEGIN_INTERVAL_TIME to the END_INTERVAL_TIME in the DBA_HIST_SNAPSHOT view.

 SELECT O.OBJECT_NAME,O.OWNER, SUM(S.TABLE_SCANS_TOTAL) "# of FTS",(SELECT NUM_ROWS FROM DBA_TABLES T WHERE T.TABLE_NAME = O.OBJECT_NAME) "num rows total"
 FROM DBA_HIST_SEG_STAT S JOIN DBA_OBJECTS O ON (S.OBJ# = O.DATA_OBJECT_ID)
 WHERE O.OWNER NOT IN ( 'SYS','DBSNMP','XDB')
 AND O.OBJECT_TYPE = 'TABLE'
 GROUP BY S.OBJ#,O.OBJECT_NAME,O.OWNER
 ORDER BY 4 DESC;

OBJECT_NAME	OWNER	# of FTS	num rows total
TABLE1	USER1	5702	1583895743
TABLE2	USER1	11	588921781
TABLE3	USER1	6195	241550246

As can be seen from above, the extreme number of rows in TABLE1, coupled with 5702 full table scans, should bring it to your attention as a candidate for partitioning!