CINAHL (Cumulative Index for Nursing and Allied Health)
Instrument description information can be found by entering the search string: research instrument.pt. (pt=publication type) or by using words from the title of a particular instrument.
See also Duke's research instruments in CINAHL guide.

MEDLINE
Helpful MESH headings for the concept of tests and measurement include: questionnaires, psychological tests, psychometrics outcome, and process assessment (health care). Database may be searched using important words from the title of a particular instrument.

Buros Center for Testing
Publishers of the Mental Measurements Yearbook and Tests in Print. Allows one to search for tests part of the Mental Measurements Yearbook in the Test Reviews Online search engine.

The Medical Algorithms Project
More than 5,100 algorithms (computation, formula, survey, or look-up table) are maintained at this site by the Institute for Algorithmic Medicine.

ProQolid:  The Patient-Reported Outcome and Quality of Life Instruments Database
Describes more than 480 Patient-Reported Outcomes (PRO) measures.  Full access only available via an annual subscription.

Tests and Measures in the Social Sciences
A listing of nearly 14,000 measures in 83 resources created by Helen Hough, a Health Sciences Librarian at the University of Texas at Arlington.