Created by the National Center for Biotechnology Information, PubMed is a database which focuses broadly on life sciences. This database contains all MEDLINE citations as well as out-of-scope records, author manuscripts, records not indexed in MEDLINE, and more. This database is freely accessible to the public.
Scimago measures the scientific influence of scholarly journals that accounts for both the number of citations received by a journal and the importance or prestige of the journals where such citations come from.
Offers a systematic, objective means to critically evaluate the world's leading journals, with quantifiable, statistical information based on citation data. By compiling articles' cited references, JCR helps to measure research influence and impact at the journal and category levels, and shows the relationship between citing and cited journals.