The Disease Ontology browser is a web application that allows for exploration of the Disease Ontology. It allows for full text searching over the whole ontology, advanced searches for: disease name, synonym, definition, subset, DOID, alternative ID, Xrefs (disease vocabulary cross references), as well as visualization of relations between nodes.
The Disease Ontology OBO and OWL files are updated (in DO's GitHub) daily, as a formal data release monthly.
The DO's API can be queries using DO Identifiers (DOID) using the URL:http://www.disease-ontology.org/?id=DOID:9256
In the Advanced Search box, you can include multiple search terms to create a complex query, by clicking on "Add New Field" and specifying your Boolean query (AND, OR, NOT) from the Advanced Search menu.
The DO files are documented in DO's GitHub in README_DO_Files
The most up to date DO files can be downloaded from DO's GitHub repository, in the DiseaseOntology/HumanDiseaseOntology/src/ontology direcory.
New terms, definitions, suggestions and questions regard the Disease Ontology can be submitted to the DO Term Tracker