SciFinder uses the Tanimoto algorithm to compare all substances in the database with your query structure, and then determines which are the most similar.

Similarity searching is complementary to the other structure searches because it returns many answers that are neither exact nor substructure answers. 

Mouse over the tool buttons to see names or descriptions for the tools. Once you select a tool, information also displays above the drawing area. For details about drawing structures and using each of the tools, see the SciFinder Help files. Note: Similarity searches cannot be done with structures that contain: R-groups, variables, repeating groups, or variable attachment positions Multiple fragments Stereo bonds

Select Similarity search, and specify any filters that you would like to apply to your search. Click OK.

SciFinder groups substance results by similarity score. Substances with the highest scores are most similar to your query structure.  Select the group(s) of interest, and click Get Substances.