Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Percentage of publications listed in the United States National Library of Medicine (https://www.ncbi.nlm.nih.gov/pubmed/, 12-3-2018) for years 1900 through 2018 (a), 1960 through 2018 (b) and 2000 through 2018 (c), containing the keyword “hydroxyapatite” normalized to the total annual number of publications retrievable using the keyword “medicine”.
