20. CHANGES IN PLASMA MATRIX METALLOPROTEINASE-9 CONCENTRATIONS IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE IN AND OUT OF EXACERBATION AT MILITARY HOSPITAL 103 IN 2023. YHCĐ. 2024;65(CĐ 3 - Bệnh viện Phổi Trung ương). doi:10.52163/yhc.v65iCD3.1116