From the Agency for Healthcare Research (AHRQ), U.S. Department of Health and Human Services.

This is a Library EBSCO database. Scroll down to Publication Type and select Practice Guidelines.

This is a Library EBSCO database. Look for the Evidence-Based Care Sheets tab on top toolbar.

Produced by the National Library of Medicine, MEDLINE provides authoritative information on medicine. Access to MEDLINE is provided through a Library EBSCO database. To limit your search to guidelines: on the search screen scroll down to Publication Type and select Guideline or Practice Guideline.

This is a fee-based database, but some Summary Sheets are free.