title: ANOMALOUS CONTRAST IN ELECTRON MICROGRAPHS OF NEGATIVE STAINED SPECIMENS.
mesh_terms: D004396:Coloring Agents; D004583:Electrons; D008853:Microscopy; D008854:Microscopy, Electron; D012106:Research; D013194:Staining and Labeling; D014414:Tungsten; D014616:Vaccinia virus
chemical_list: D004396:Coloring Agents; D014414:Tungsten
keywords: EXPERIMENTAL LAB STUDY; MICROSCOPY, ELECTRON; STAINS AND STAINING; TUNGSTEN; VACCINIA VIRUS