根据混合物中分子量大小不同而进行分离的方法是

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SQL Error: select id,body,options from ***_enewstiku where sourceid='30714' and id < 2474552 and id<>'2474552' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='30714' and id > 2474552 and id<>'2474552' order by id asc limit 5