"PubMed is a free resource that is developed and maintained by the National Center for Biotechnology Information (NCBI), at the U.S. National Library of Medicine (NLM), located at the National Institutes of Health (NIH). PubMed comprises over 29 million citations for biomedical literature from MEDLINE, life science journals, and online books. PubMed citations and abstracts include the fields of biomedicine and health, covering portions of the life sciences, behavioral sciences, chemical sciences, and bioengineering. PubMed also provides access to additional relevant web sites and links to the other NCBI molecular biology resources." https://www.ncbi.nlm.nih.gov/books/NBK3827/#pubmedhelp.PubMed_Quick_Start
To learn more about resources available through PubMed, https://www.ncbi.nlm.nih.gov/pubmed
Their quick start guide is available at: https://www.ncbi.nlm.nih.gov/books/NBK3827/#pubmedhelp.PubMed_Quick_Start
PubMed can be accessed through Databases by title as well as online.
The National Center for Biotechnology Information (NCBI), a division of the U.S. National Library of Medicine, provides access to scientific and biomedical databases, software tools for analyzing molecular data, and performs research in computational biology. Here is a video on extracting citations from PubMed and using a NCBI account.