Document Type : Original
Authors
1 Department of pulmonary diseases, Mashhad University of Medical Sciences, Mashhad, Iran
2 Department of statistics, Mashhad University of Medical Sciences, Mashhad, Iran
3 Ear, Nose, Throat, Head and Neck surgery Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
4 Department of internal medicine, Mashhad University of Medical Sciences, Mashhad, Iran
Abstract
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