435 / | HD | CHEMISTRY: MOLECULAR BIOLOGY AND MICROBIOLOGY |
41 | DF | MICRO-ORGANISM, TISSUE CELL CULTURE OR ENZYME USING PROCESS TO SYNTHESIZE A DESIRED CHEMICAL COMPOUND OR COMPOSITION {26} |
117 | DF | .~ Preparing heterocyclic carbon compound having only O, N, S, Se, or Te as ring hetero atoms {4} |
123 | DF | .~.~ Oxygen as only ring hetero atom {3} |
125 | .~.~.~ Containing six-membered hetero ring (e.g., fluorescein, etc.) |