Sources
Where the evidence comes from.
Symmathy queries each source through its public API or licensed gateway. Every claim shown in a summary or chat answer links back to its origin record.
PubMed / MEDLINE
The US National Library of Medicine's flagship index. 37M+ citations across every major biomedical journal back to 1966, with structured MeSH subject indexing. The default first stop for clinical literature in English.
US · curated
Europe PMC
European mirror of MEDLINE plus the full PubMed Central open-access archive and the major preprint servers (bioRxiv, medRxiv, ChemRxiv). Often surfaces full-text links PubMed alone won't.
EU + preprints · curated
Cochrane Library
The gold-standard source for systematic reviews and meta-analyses. Cochrane reviews synthesize all available trials on a clinical question using rigorous, pre-registered methodology — the top of the evidence pyramid.
International · highest evidence tier
ClinicalTrials.gov
The world's largest registry of clinical studies, run by the US NIH. 490k+ trials with protocols, eligibility criteria, sponsor, recruitment status, and (when posted) results. Essential for spotting unpublished or in-progress evidence.
Global trial registry
J-STAGE
Japan Science and Technology Agency's platform for Japanese-published biomedical research. Covers thousands of society journals — much of which never reaches PubMed — with English abstracts.
Japan & Asia · curated
LILACS
BVS / BIREME's regional health sciences index. The authoritative source for Brazilian, Argentine, Mexican, Chilean, and Caribbean medical research, including tropical disease and public health work absent from US/EU databases.
Latin America & Caribbean · curated
DOAJ
Directory of Open Access Journals — a vetted whitelist of legitimate OA journals worldwide. Strong coverage of African, Asian, and Latin American medical research from journals that pass editorial-quality screening.
Open access · curated
HAL
France's national open archive, run by CNRS. The primary index for French and francophone life-sciences research, including INSERM, Institut Pasteur, and university medical centers — much of which is not indexed in PubMed.
France & Europe · curated
OpenAlex
Open replacement for Microsoft Academic. ~250M scholarly works with the broadest non-Western coverage available — Chinese, Thai, Israeli, Middle-Eastern, and African journals. Unfiltered, so quality varies; use alongside curated sources.
Global · aggregated
CrossRef
The DOI registration agency for almost every academic publisher on Earth. Used here as the broadest possible metadata net — surfaces papers from publishers that don't appear in any disciplinary index, and helps deduplicate hits across sources.
Cross-publisher · aggregated
ThaiJO
Thai Journals Online — the TCI national platform hosting Thai-published biomedical research, much of which never appears in PubMed or OpenAlex. ThaiJO has no unified search API, so Symmathy harvests its per-journal OAI-PMH feeds nightly into a local index, scoped to TCI health-sciences journals.
Thailand · harvested locally
KoreaMed
The Korean Association of Medical Journal Editors' index of major Korean biomedical journals — JKMS, JKMA, KJIM, KJFM, and ~250 others. Most records link out to open-access full text via KoreaMed Synapse. Queries are translated into Korean to surface records whose metadata is only in Korean.
Korea · curated (KAMJE)