This is the federation starship Enterprise NCC-1701-C, Ambassador class. This ship made a one time appearance in the Next Generation episode "Yesterday's Enterprise". I'm pretty sure the Ambassador class has been seen in other episodes, though.
I partly agree with the person below, but you have an almost perfectly accurate side of the ship! Proportions look nice. I'll rate 5/5, because this is the best of the few on this site.
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