2026 Rule-based natural language processing to extract clinical trial and research study enrollment history from unstructured notes. Sergey D. Goryachev†, Julie Tsu-Yu Wu†, Eric Lin†, Daphne R. Friedman, Robert Zwolinski, Rupali Dhond, Danne C. Elbers, Jennifer La, Cenk Yildirim, June K. Corrigan, Daniel C. R. Chen, Mary T. Brophy, Nhan V. Do‡, Nathanael R. Fillmore‡† Equal first authorship · ‡ Equal senior authorship Health Informatics Journal32(1), 14604582261430614 U.S. Veterans and VA Data Electronic Health Records Natural Language Processing Rule-Based Algorithms Clinical Notes