在一定范围内的某种放射性核素在单位时间内发生核素衰变的次数被称为

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SQL Error: select id,body,options from ***_enewstiku_ where sourceid='10895' and id < 866308 and id<>'866308' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='10895' and id > 866308 and id<>'866308' order by id asc limit 5