Indexing is considered as a reflection of journal quality. Indexed journals are considered to be of higher scientific quality as compared to non-indexed journals.
Some of the Major Indexing Sites
Indexed in Google Scholar, ResearchGate, Cross Ref, Scilit, Semantic Scholars, Publons, H-Index, Directory of Research Journals Indexing (DRJI) and PSIthority, etc.
Science Citation Index Expanded (SciSearch), Journal Citation Reports/Science Edition, Medline, SCOPUS, Chemical Abstracts Service (CAS), Calcium and Calcified Tissue Abstracts, EBSCO Biomedical Reference Collection, EBSCO Dentistry & Oral Sciences Source, EBSCO Discovery Service, EBSCO TOC Premier, EMCare, Gale, Gale Academic OneFile, OCLC WorldCat Discovery Service, ProQuest Biological Science Database, ProQuest Central, ProQuest Health & Medical Collection, ProQuest Health Research Premium Collection, ProQuest Medical Database, ProQuest Natural Science Collection, ProQuest Pharma Collection, ProQuest Research Library, ProQuest SciTech Premium Collection, ProQuest-ExLibris Primo, ProQuest-ExLibris Summon