"PubMed is a free resource developed and maintained by the National Center for Biotechnology Information (NCBI) at the National Library of Medicine® (NLM)."
PubMed is the standard database that is used in the healthcare profession. It has the ability to link to full-text articles, provides advance researching including filtering and special queries and links to related articles.
The search function is extremely user-friendly and the filtering options allow for searching clinical trials, full text, and even publication dates. The search function also provides related searches and data. Once an article is selected, similar articles are included in the record.
Citations are added daily.
From: PubMed Fact Sheet
"Simply enter your search topics - one or more terms - and click Search. PubMed can be searched using MeSH terms, author names, title words, text words or phrases, journal names, or any combination of these.
Retrieved citations are displayed and their associated abstracts can be selected for viewing. A unique feature of PubMed is the ability to instantly find related articles for any citation.
Advanced search features and filters are also available.
A special clinical queries page provides customized searches for studies based on etiology, diagnosis, prognosis, or treatment of a particular disease. Systematic reviews of a topic and medical genetics can also be searched here. Search results can be viewed or downloaded in various formats, including a format suitable for bibliographic management software."