As well as our secondary evidence content, Trip also includes a large number of journal articles. The coverage is complicated and this post sets out what we include, journal wise, in Trip.
Key Primary Research: We include all the journal articles from the big 5 internal medicine journals – NEJM, Lancet, JAMA, BMJ and Annals of Internal Medicine. In addition we include all the content from the wonderful EvidenceAlerts.
PubMed’s core content: We include all the articles from PubMed’s core content (~110 journals)
Additional journal coverage: For our clinical areas (we have around 30 and cover topics such as cardiology, oncology) we selected the top journals based on Impact Factor for each area. These were then reviewed to ensure they were clinically focussed (many are at the academic scale of things, so these were excluded).
In total we grab all the articles from around 550 journals.
Randomised controlled trials (RCTs): We grab all the randomised controlled trials from ANY journal in PubMed (I believe they cover 5000 journals).
Systematic Reviews: As with RCTs we attempt to grab all the systematic reviews from PubMed. And we have a separate system to identify systematic reviews in non-PubMed journals.
In total we have approximately 4.5 million journal articles (compared to 33 million in PubMed).
Full-text: Final point! For Pro subscribers we offer links to full-text to approximately 70-75% of all our journal articles (~ 3.1-3.4 million articles).