Find Substances Using Search Terms

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There are two ways to finds substances using search fields:

  • Main search field - Substance name, CAS Registry Number, patent identifier, notes, and DOI. The search field has a 2000-character limit. See Substance Search Terms for all input types. You may enter multiple terms in the search field separated by a space, no commas or other punctuation. 

  • Advanced Search Field(s) - Boolean operator (AND, OR, NOT) + search field values, molecular formula, experimental spectra, and the following property categories: biological/chemical, density, electrical, Lipinski, magnetic, mechanical, optical and scattering, structure related, and thermal.

You may use the search field and Advanced Search Fields separately or in combination.

For example, I'll enter the patent number WO2010071837 in the search field. 


This search returns 1,157 substance results with at least one associated reference containing WO2010071837.


Next, I'll add some Advanced Search Fields:

  • NOT Biological > Median Lethal Dose (mg/kg): >160
  • AND Thermal > Melting Point (°C): <220



  • Check the Search key property values only box available for the below properties to focus the property query only on data found in a substance's Key Physical Properties box or preferred substance values:
    • Median Lethal Dose (mg/kg)
    • Density (g/cm3)
    • Electric Conductance (S)
    • Electric Conductivity (S/cm)
    • Electric Resistance (ohm)
    • Electric Resistivity (ohm*cm)
    • Magnetic Moment (muB)
    • Tensile Strength (Mpa)
    • Optical Rotatory Power (degrees)
    • Refractive Index
    • Boiling Point (°C)
    • Glass Transition Temperature (°C)
    • Melting Point (°C)
  • The value(s) in the search field are combined with the output of the Advanced Search Fields (operators are processed in OR/AND/NOT order): WO2010071837 NOT (Median Lethal Dose (mg/kg): >160 AND Melting Point (°C): <220). Important: The first operator selected determines the relationship of Advanced Search Fields and operators to any terms entered in the search field.
  • You may change the order of the fields by clicking the Drag icon (SFn-DragFieldIcon.png) and moving the field.




This search returns 1,122 results containing WO2010071837 that also do not have a Median Lethal Dose greater than 160 mg/kg and a Melting Point less than 220°C.


To edit the Advanced Search Fields from the results page, click the Edit Search button in the Substances search field.



Substance Search Terms

Search field terms may be:

  • Substance Name:
    • Example: benoxaprofen
      Note: Wildcard searching using an asterisk only works for single-search-term, single-word substance name searches (e.g., benoxa*). Partial substance names without a wildcard character will not return results.
    • Example: methyl ethyl ketone
      Note: For an exact match, use double quotes around the substance name. Searching multiple word substance names without quotes also returns results matching part of the name. For example, searching the above example without double quotes returns methyl ethyl ketone, methyl, ethyl ketone, and ethyl.
    • Examples: amyloid ß, sigma bonds, interferon .alpha.
      Note: For more information, see Greek Letters and Equivalents Used in Searching.
  • CAS Registry Number (with or without dashes, e.g., 51146-57-7, 51146577)
    Note: Square brackets are accepted around RNs (e.g., [51146-57-7], but not single or double quotes.
  • Notes: Used to search within fields such as reaction notes and substance notes.
  • Document Identifier:
    • Patent Number (no spaces, e.g., US4571400)
    • Accession Number (e.g., 1986:230471)
    • PubMed ID Number (e.g., 15980585)
    • CAS Accession Number (CAN): document number in CA Plus (e.g.,148:486341)

As you enter the text, autosuggestions may appear; you can select from the list of suggestions or continue typing. Click the magnifying glass to submit the query.


Using Multiple Terms

You may search for substances by entering multiple terms such as substance names, CAS Registry Numbers (RNs), and document identifiers like patent, accession, and PubMed ID numbers in the search field.


For example, the query methyl ethyl ketone 15687-27-1 "phenyl bromomethyl sulfone" 98113 returns the following result numbers: 

1. 15687-27-1: CAS RN in the query.

2. 98-11-3: CAS RN matched to 98113 in the query.

3. Methyl ethyl ketone: substance name in query. Since the name does not appear in quotes, each word may be matched to a substance:

    1. Methyl
    2. Ethyl ketone
    3. Ethyl

4. Phenyl bromomethyl sulfone: quoted substance name in the query.

5. Mg: substance indexed in a MEDLINE reference with a PubMed ID matching 98133 in the query.

6. F: substance indexed in a MEDLINE reference with a PubMed ID matching 98133 in the query.