Notts County's relegation fears intensified with a 0-0 home draw against Coventry.In a game which offered precious few chances between two struggling sides, Hayden Mullins almost opened the scoring with a blistering 25-yard drive which forced a good save from visiting goalkeeper Lee Burge.Coventry offered very little going forward in the first half, but began to up the ante in the second half as they searched for a priceless win.Adam Barton wasted a great chance to give them the lead when he snuck in at the back post but could only volley wide of the target.That prompted a quick response from Notts and the woodwork denied them a goal when Garry Thompson flicked a header onto the foot of the post.And when Liam Noble was introduced from the bench, the midfielder bent a shot just over the crossbar following some good approach play.But it was Coventry who nearly snatched it at the death when Barton forced Roy Carroll into a brilliant save from point-blank range.