Use the keyword query for simple searches of:

Chemicals
Search by MeSH® name, synonym, accession ID (“MESH:…”), or CAS Registry Number. To limit your search to official names, use the “name:” prefix.
Diseases
Search by MeSH name, synonym, OMIM accession ID (“OMIM:…”), or accession ID (“MESH:…”). To limit your search to official names, use the “name:” prefix.
Genes
Search by NCBI (Entrez) Gene symbol, name, synonym, or accession ID (“GENE:…”). To limit your search to official symbols, use the “name:” prefix.
Gene Ontology
Search by name, synonym, or GO ID (“GO:0008219” or “8219”). To limit your search to official names, use the “name:” prefix.
Organisms
Search by NCBI Taxonomy scientific name, common name, synonym, or accession ID (“TAXON:…”). To limit your search to official scientific names, use the “name:” prefix.
Pathways
Search by KEGG or REACTOME name or accession ID (“KEGG:…” or “REACT:…”). To limit your search to official names, use the “name:” prefix.
References
Search by author (“lastname initials”), title, abstract, PubMed® ID, or DOI (Digital Object Identifier).

Queries are not case sensitive.

An asterisk (*) can be added as a wildcard, but only at the end of a word.

You can combine multiple terms in one query using the & (AND) and | (OR) Boolean operators.

For more sophisticated queries, use the advanced Chemical–Gene Interaction, Gene, or Reference query.