- identifier
- A vector of identifiers, either numeric or character.
The type of identifier depends on the - namespaceand- domainparameters.
**Note**:- identifiermust be provided; it cannot be- NULL.
 
- namespace
- A character string specifying the namespace of the identifier. - Possible values depend on the - domainparameter and include:
 - - For - domain = 'compound':- cid,- name,- smiles,- inchi,- sdf,- inchikey,- formula, etc.
 - - For - domain = 'substance':- sid,- sourceid/<source id>,- sourceall/<source name>,- name, etc.
 - - For - domain = 'assay':- aid,- listkey,- type/<assay type>,- sourceall/<source name>, etc.
 - For more details, see the Input section. 
- domain
- A character string specifying the domain of the query. - Possible values are: - - - compound(default)
 - - - substance
 - - - assay
 - - Other domains as specified in the API documentation. 
- searchtype
- An optional character string specifying the search type. - Possible values depend on the - namespaceand- domain.
 - Examples include: - - - substructure,- superstructure,- similarity,- identityfor structure searches.
 - - - fastidentity,- fastsimilarity_2d,- fastsimilarity_3d, etc. for fast searches.
 - If - NULL(default), no search type is specified.
 
- options
- A list of additional options for the request. - Available options depend on the specific request and the API. - Examples include: - - For similarity searches: - list(Threshold = 95)
 - - For substructure searches: - list(MaxRecords = 100)
 - If - NULL(default), no additional options are included.
 - For more details, see the Structure Search Operations section of the PUG REST API.