Try this database first when searching for tests. PsycTESTS provides full-text copies of many tests as well as supporting documentation.
You may find the following APA blog articles on PsycTESTS helpful:
Getting Started with APA PsycTESTS: What is it and how can it help me?
Getting Started with APA PsycTESTS: FAQ's - Using a Test You've Found
You can use PsycINFO to find information about tests and sometimes the tests themselves.
Once you have identified some tests/measures, you can search to see what studies have used these.
You can also search for tests that are included in an article:
Or you can search for a test name AND the word appended to see if any articles have the test included with the article.
Health and PsychoSocial Instruments (HaPI)
Limit your search by checking the box for "primary source." In HaPI, a primary source is either the original article where the instrument was first used or a resource that contains the full-text of the instrument.