Scientific technicians were Starfleet technicians who specialized as scientific researchers aboard Federation starships.
After Spock determined that the radiation induced hyper-aging condition that affected the landing party gave its victims less than a week to live, Captain James T. Kirk requested that he wanted all of the USS Enterprise's research facilities and scientific technicians to start round-the-clock research immediately, in order to find a remedy for the condition. (TOS: "The Deadly Years")