expdp
Note: It will create a consistent dumpfile, which can be used to import full database, schema etc.
expdp \"/ as sysdba\" FLASHBACK_TIME=\"TO_TIMESTAMP\(TO_CHAR\(SYSDATE,\'YYYY-MM-DD HH24:MI:SS\'\),\'YYYY-MM-DD HH24:MI:SS\'\)\" directory=DIR_NAME full=y dumpfile=full_DB.dmp logfile=full_db.log compression=all
impdp
Note: While importing you need not to mention the flashback option.
impdp \'/ as sysdba\' directory=DATAPUMP_DIR dumpfile=full_DB.dmp logfile=impfull_db.log full=y