Although there is not one single method to locate measures, there are a number of strategies that can help you.
CHIPTS Instrument Bank
Directory of instruments used by the Center for HIV Identification, Prevention, and Treatment Services at UCLA. Browse alphabetically or by subject category. Instruments are attached in PDF.
HSRR (Health Services and Sciences Research Resources)
A database available from the National Information Center on Health Services Research and Health Care Technology (NICHSR). Search by Instruments/Indices.
Industrial/Organizational Psychology Scale Page
Scales from Paul E. Spector, organizational psychology researcher at the University of South Florida.
Measuring Intimate Partner Violence, Victimization and Perpetration: A Compendium of Assessment Tools
From the Centers for Disease Control and Prevention (CDC). Contains over 20 scales.
Measuring Violence-Related Attitudes, Beliefs and Behaviors and Influences Among Youths: A Compendium of Assessment Tools
From the Centers for Disease Control and Prevention (CDC). Contains over 170 downloadable measures.
A multi-university research collaboration between the University of Washington, Harvard, and University of Virginia. Register for free to take online tests that measure unconscious feelings and preferences regarding 90 varied topics by rapid categorization of words and images. Demonstration tests not requiring registration are also available. Test takers can view results in comparison to other respondents. Also provides full-text research studies that have used the tests.
Social Personality Psychology Questionnaire Instrument Compendium
A directory of tests maintained by Dr. Alan Reifman of Texas Tech University. If the complete test has been put online by its author, there will be a link to the test. If not, there will be a link to the test author's website or affiliated organization.
Hamilton Depression Rating Scale
This online depression scale was developed at Palo Alto Veterans Affairs Hospital by Wes Ashford, M.D., Ph.D.
Inventory of Depressive Symptomatology (IDS) and Quick Inventory of Depressive Symptomatology (QIDS)
This test is offered in multiple languages by University of Pittsburgh Epidemiology Data Center.