Getting Better Results with MedLine

Selection of journals for Medline is pretty stringent

"Journal Selection for MEDLINE

The National Library of Medicine (NLM) decides whether the scientific and editorial character and quality of a journal merit its inclusion in MEDLINE. In making this decision, NLM considers scientific policy set by the NLM Board of Regents, the suitability of the journal for the NLM Collection (according to the criteria in the Collection Development Guidelines), as well as the recommendations of an NIH Federal Advisory Committee, the Literature Selection Technical Review Committee (LSTRC).

The LSTRC consists of fifteen members, including scientists (i.e., Ph.D.- or M.D.-level researchers and physicians) and medical librarians. The LSTRC generally reviews articles from the last two years of journal content and evaluates them primarily based on scientific and editorial quality.

MEDLINE’s Scientific Quality Review is a rigorous, multi-step process in which many factors are assessed. NLM views each journal comprehensively, rather than basing a decision on a defined list of criteria. Each title is reviewed by multiple individuals both within the NLM and the LSTRC, and final decisions are based on input from all these sources. The final decision of whether to index a journal for MEDLINE is made by the Director of the NLM.  

A description of possible considerations during the Scientific Quality Review is given below. For an overview of the MEDLINE pre-application requirements as well as a step-by-step breakdown of the MEDLINE application and review process, please see How to Include a Journal in MEDLINE."

https://www.nlm.nih.gov/medline/medline_journal_selection.html