PubChem
pubchem.ncbi.nlm.nih.govChemical structures, substances and bioassay information
Chemical structures, substances and bioassay information
A German-language full-text library and historical reference
Detailed bird life histories with maps and multimedia
Open textbooks for higher-education subjects
Curated learning-resource discovery by discipline
Academic phrasing organized by rhetorical purpose
Anatomy articles, diagrams and three-dimensional learning material
Pathology images and tutorials for medical education
An ophthalmology encyclopedia written by eye specialists
Learn and test text patterns with live feedback
Develop mobile illustrations with editable brushes and layered drawing
Animal reference searchable by information and media type
A curated registry of biological and biomedical ontologies
Controlled terminology for art and cultural-heritage research
Educational tools for examining global facts and assumptions
Shakespeare texts with scholarly and educational context
A multilingual encyclopedia with a language-aware search
Related English words for revising a draft
A versioned taxonomic catalogue of spiders
A historical London map linked to texts and reference records
Math and electrical calculations in a compact tool directory
Metric and imperial conversion with reference charts