Ovid Nursing Subject Thesaurus

"Ovid Nursing Subject Thesaurus is a proprietary Controlled Vocabulary and associated Nursing Lexicon which ‘speaks nurse’ to meet the specific needs of nursing professionals of all types and is designed to enhance retrieval of relevant documents for nursing professionals and students. (...) ONST takes the familiar terminology of Medical Subject Headings (MeSH) as a starting point. While the thesaurus is MeSH-compatible, many inverted MeSH headings, (e.g. Education, Continuing) have been flipped to direct order (e.g., Continuing Education).

Unified Soil Classification System

"The Unified Soil Classification System (USCS) is a soil classification system used in engineering and geology to describe the texture and grain size of a soil. The classification system can be applied to most unconsolidated materials, and is represented by a two-letter symbol."


"Comprehensive and polyhierarchically structured, Emtree provides a consistent description of all biomedical terminology, allowing unrivaled drug and disease indexing.

Peace and Security Studies Thesaurus

"The Thesaurus is displayed in a hierarchical and alphabetical fashion. The Thesaurus contains 1330 subject terms, including descriptors, and cross-references. At its core, the Thesaurus is meant to provide standardized terminology in the field of peace and security studies. As a controlled vocabulary, the Thesaurus addresses the information retrieval needs of the international affairs community by providing context for search terms."