Here’s a comprehensive list of field tags (or qualifiers) you can use in NCBI queries to refine your search results. These tags help you specify which part of the record you want to search within. The exact tags available can vary depending on the database you're querying, but here are some common ones:

Common Field Tags for NCBI Queries

1. [ORGN]: Organism

   • Example: West Nile Virus[ORGN]

2. [GENE]: Gene name

   • Example: BRCA1[GENE]

3. [PROT]: Protein name

   • Example: p53[PROT]

4. [TAXON]: Taxonomy ID

   • Example: 9606[TAXON] (for humans)

5. [TITLE]: Title of the article or record

   • Example: cancer research[TITLE]

6. [AUTHOR]: Author of the article

   • Example: Smith[AUTHOR]

7. [JOURNAL]: Journal name

   • Example: Nature[JOURNAL]

8. [PMID]: PubMed ID

   • Example: 12345678[PMID]

9. [DOI]: Digital Object Identifier

   • Example: 10.1038/nature12345[DOI]

10. [SUBSTANCE]: Chemical substance

    • Example: Aspirin[SUBSTANCE]

11. [CLINICALTRIAL]: Clinical trial ID

    • Example: NCT00012345[CLINICALTRIAL]

12. [COMP]: Compound

    • Example: Caffeine[COMP]

13. [SNP]: Single nucleotide polymorphism

    • Example: rs123456[SNP]

14. [PROTEIN]: Protein-related information

    • Example: Hemoglobin[PROTEIN]

15. [VARIANT]: Genetic variant

    • Example: BRCA2 variant[VARIANT]

16. [SERIES]: Series of experiments or datasets

    • Example: GSE12345[SERIES] (for GEO series)

17. [ACC]: Accession number

    • Example: NM_001301717[ACC]

18. [DB]: Database

    • Example: NCBI[DB]

19. [PATENT]: Patent number

    • Example: US1234567[PATENT]

20. [DATABASE]: Database field

    • Example: NCBI[DATABASE]

Examples of Usage:

• Searching for Articles by Title:

  cancer immunotherapy[TITLE]

• Finding Research by Author:

  Smith[AUTHOR]

• Locating Specific Genes:

  TP53[GENE]

• Looking for Proteins:

  Hemoglobin[PROT]

• Searching by PMID:

  12345678[PMID]

These field tags help you focus your search on specific aspects of the data, making it easier to find exactly what you're looking for in the vast amount of information available in NCBI's databases.