 medlin evalu studi medlin medlar-on-line on-line interact bibliograph search system develop nation librari medicin the system user list bibliograph citat three-year file 1 250 biomed journal a survei test user reaction conduct univers virginia medic librari the survei base repli 246 user request medlin search septemb 1972 march 1973 the find indic 93 medlin substanti improv tradit method search print index these respond state medlin search assist clinic work ask continu medlin imposit user charg juli 1 1973 75 the remain 25 express reserv doubt the survei reason imposit user charg medlin declin 