To find clinical trials,

• go to clinicaltrials.gov
• condition/disease: enter "osteoporosis"
• location:
  • enter your zip code
  • enter how far you are willing to travel
• study status: choose between "all studies" and "recruiting and not yet recruiting studies"
• click Search button
• search results should appear
• click on the header for a specific study
• see the menu on the left to get more info about locations and participation criteria

It is also informative to widen the search (i.e. just use "osteoporosis") to find what studies are ongoing.