Types of structure searches: Closed substructure search (CSS)

CSS search retrieves substances which match the query exactly
- All positions in query are blocked for further substitution
- All query rings are isolated
- Variable nodes are allowed in the query
- Retrieves all substances having the same connection table
  - Unsubstituted substance
  - Stereoisomers
  - Isotopically labelled substances
  - Radicals
  - Ions
  - Homopolymers
- Retrieves multi-component substances that have the query as one of the components
Any position may be opened to substitution by specifying the connectivities for the node