Exact 2D structure search

Exact 2D structure search All entries in the database that match exactly and completely to a unique query stracture have to be retrieved. The structures can be retrieved rapidly by using hashed lexicographic codes. ... 

Fuzzy 2D substructure searching is an extension of substructure searching to the minor extent that it permits the expansion of the query formulation vocabulary to include topological features and substructural wildcards described above. This involves the retrieval of all entities in a CIR system that contain the user-defined partial structure and that satisfy whatever wildcard specification pattern has been specified. The query identifies the partial structure and simple wildcard substitution patterns exactly. As with substructure searching, the use of query features on a partial structure will always identify structures which are equal in size or larger than the query. 

The Registry File (2D) may be searched via such services as STN (Science and Technology Network), using a variety of retrieval modes including exact structure, substructure, and similarity search. 

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