The PubMed interface we all know and love, and have been used to for decades, is getting a makeover.
To bring the face of the world's most popular biomedical literature database into the 21st century, NCBI (The National Center for Biotechnology Information), a division of NLM (the National Library of Medicine), is unveiling a new mobile-friendly main page, with a fundamentally different underlying database-searching algorithm. That new algorithm, named Best Match, uses machine learning to tailor search results for each user based on past search histories.
This updated version of PubMed is currently available at https://pubmed.ncbi.nlm.nih.gov/ . The new PubMed will become the default in spring 2020 and will ultimately replace the legacy version. You can learn more about it in the NLM Technical Bulletin linked here.
The Best Match algorithm was introduced in a PLoS Biology paper in August of 2018. It can be found in the PubMed Central database at this link.