Catalogue of the Central Library: 
http://hunteka.lib.semmelweis.hu/

Other catalogues:
GYEMSZI hungarian hospitals Common Catalogue: http://kozkat.gyemszi.hu/

MOKKA (Hungarian National Common Catalogue): http://www.mokka.hu

Hungaricana: http://hungaricana.hu/hu/

Matarka http://www.matarka.hu/

MOKKA-R: http://www.eruditio.hu/mokka-r/

OSZK OPAC: http://nektar1.oszk.hu/librivision_hun.html

International catalogues:

WorldCat: https://www.worldcat.org/

Catalogue of Karolinska Institutet University Library (Swiss): https://kib.ki.se/en

Catalogue of National Library of Medicine (USA): http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=nlmcatalog

Deutsche Zentralbibliothek für Medizin (Germany) http://www.zbmed.de

Catalogue of The British Library (United Kingdom): http://explore.bl.uk

Catalogue of Library of Congress (USA): http://catalog.loc.gov

University of Cambridge: https://idiscover.lib.cam.ac.uk/primo-explore/search?vid=44CAM_PROD&lang=en_US&sortby=rank

Exeter Health Library: http://www.exeter.ac.uk/library/

Max Planck Institute: http://www.mpimf-heidelberg.mpg.de/facilities/library/catalogues