Almost any indistinct noise will often make a nearby deer stop and look.
I've made walking deer stop and look by making "Baat" sounds and even just going "Psst!".
Once, I had a guy tell me that yelling "Hey!" will stop running deer if they don't know you're there. He was dragging an 8pt out of the woods and said he did it and I had thought I heard someone yell "Hey!" earlier in the morning.... Next time a deer was running by me unaware, a doe at about 10 yards, I yelled "HEY!" as loud as I could. She stopped so fast that she skidded.