ClinicalTrials.Gov allows you to search for a clinical trial based on condition or disease, the name of the drug, the name of an investigator, and geography.
The National Institutes of Health offers many different resources in addition to clinicaltrials.gov to find a research trial on their website, “NIH Clinical Trials and You”.
The National Cancer Institute offers help in finding NCI-supported clinical trials.
Many local hospitals and major academic medical centers also offer the opportunity to participate in clinical research.