A substructure search displays substances that contain the structure query embedded within the chemical structure. Unless specified otherwise, the substructure must appear as drawn, and any substituent is allowed at any open atom position.
When searching for substances, you can apply substructure query features to narrow or broaden the search for the substructures embedded in the substances matched:
Variable atom to represent a class of substituents, such as halogens
R-group to specify a list of allowed substituents
Unspecified bond type to allow any bond type
Repeating group to allow ring or chain size to vary
Variable attachment points to allow position of a ring substituent to vary
Lock Atom to prevent substitution at an atom site
Lock Ring to prevent ring fusion or formation
Drawing Repeating Groups (Video)
Drawing Variable Attachment Points (Video)