gsrs_all                Retrieve comprehensive GSRS data for a set of
                        UNIIs
gsrs_browse             Browse all substance records in GSRS
gsrs_chem_info          Retrieve chemical structure information by
                        substance name or CAS number
gsrs_codes              Retrieve external codes and identifiers for
                        GSRS substances
gsrs_hierarchy          Retrieve the relationship hierarchy for GSRS
                        substances
gsrs_names              Retrieve all names (synonyms) for GSRS
                        substances
gsrs_search             Search the GSRS substance database
gsrs_structure          Retrieve chemical structure data for GSRS
                        substances
gsrs_structure_search   Search GSRS by chemical structure
gsrs_substance          Fetch a GSRS substance record by UNII
gsrs_unii_from_name     Look up UNII codes for substance names
gsrs_vocabularies       Retrieve controlled vocabulary terms from GSRS
write_dataframes_to_excel
                        Write a named list of data frames to an Excel
                        workbook
