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Linking to This Site

Contents

The National Library of Medicine (NLM) invites you to link from your Web site to ClinicalTrials.gov.

The data on ClinicalTrials.gov change nightly. New studies are published to the Web site and existing studies are updated every day. To ensure that the most up-to-date and accurate information is provided to the public, please do not make static copies of studies or search results. Instead, use a link to the ClinicalTrials.gov site to perform a new search or display the latest version of an existing study.

For Web crawler programs, pages of links to all studies are generated each time the study collection is updated.

Review ClinicalTrials.gov Terms and Conditions

Use of ClinicalTrials.gov data is subject to these Terms and Conditions. If you link to this site, please provide proper attribution to NLM and ClinicalTrials.gov.

Linking to the ClinicalTrials.gov Home Page

The text in the left column of the table below is the HTML for a link to the ClinicalTrials.gov home page. You can copy and paste the block of HTML text directly into your Web page. Please observe the form of the ClinicalTrials.gov name: an uppercase C and T, a lowercase g, and no space between "Clinical" and "Trials."

Linking to the ClinicalTrials.gov Home Page
HTML Text Result Displayed in Browser
<a href="http://clinicaltrials.gov" title="Information on Clinical Trials and Human Research Studies">ClinicalTrials.gov</a> provides patients, their family members, and the public with easy and free access to information on clinical studies for a wide range of diseases and conditions. ClinicalTrials.gov provides patients, their family members, and the public with easy and free access to information on clinical studies for a wide range of diseases and conditions.

Linking to a Study Record on ClinicalTrials.gov

Every study on ClinicalTrials.gov is assigned a unique number called the ClinicalTrials.gov Identifier (NCT Number). A specific study can be displayed with a link that ends with that study's unique NCT Number. For example:

http://clinicaltrials.gov/show/NCT00004451

If you are viewing a study on ClinicalTrials.gov in Full Text View, the NCT Number is in the first table near the top of the page and under More Information at the bottom of the page.

For example, the text in the left column of the table below is the HTML for a link to the study with the ClinicalTrials.gov Identifier NCT00004451.

Linking to a Study Record on ClinicalTrials.gov
HTML Text Result Displayed in Browser
<a href="http://clinicaltrials.gov/show/NCT00004451" title="Study NCT00004451"> Randomized Study of the Effects of Glucose on Cognition in Healthy Young and Elderly People and Parkinson's Disease Patients </a> Randomized Study of the Effects of Glucose on Cognition in Healthy Young and Elderly People and Parkinson's Disease Patients

Links That Search ClinicalTrials.gov

You can also construct links that will search ClinicalTrials.gov. The search results are the same as those produced by filling in the Advanced Search form and clicking on the Search button. You can perform a specific search by constructing a link that ends with search terms encoded as URL parameters. For example:

http://clinicaltrials.gov/search?cond=heart+attack

Standard URL encoding rules apply:

  • Parameter lists begin with a "?" character and are separated by "&" characters.
  • Spaces are replaced with "+" characters.
  • Special characters are replaced with "%" characters, followed by their ASCII code in hexadecimal.

The following parameters are recognized:

Recognized Search Parameters
Parameter Purpose
term Generic search
cond Targeted search for conditions
intr Targeted search for interventions
outc Targeted search for outcomes
spons Targeted search for sponsors and collaborators
recr Restricts search to a specific Recruitment Status: open (recruiting or not yet recruiting) or closed (no longer recruiting) studies
Two values are recognized: recr="open" and recr="closed"

Additional parameters are recognized, but they are more likely to change over time. If you are an experienced HTML developer, inspection of the HTML for the Advanced Search page will show you which parameters are currently in use. Advanced search links using additional parameters should be checked routinely to ensure functionality.

Examples of Searches

  1. Search by term, condition, or sponsor or collaborator.

    General search for the term "pediatric" on ClinicalTrials.gov:
    <a href="http://clinicaltrials.gov/search?term=pediatric">pediatric</a>

    Targeted search for the condition "diabetes" on ClinicalTrials.gov:
    <a href="http://clinicaltrials.gov/search?cond=diabetes">diabetes</a>

    Targeted search for the sponsor or collaborator "NHLBI" on ClinicalTrials.gov:
    <a href="http://clinicaltrials.gov/search?spons=NHLBI">NHLBI</a>

  2. Search with multiword terms. For a multiword term that should be treated as a phrase, spaces must be replaced with "+" characters and the entire phrase must be enclosed in quotation marks, which are URL encoded as "%22."

    Targeted search for the condition "heart attack" on ClinicalTrials.gov:
    <a href="http://clinicaltrials.gov/search?cond=%22heart+attack%22">"heart attack"</a>

  3. Search with multiple clauses. A search with multiple clauses should have the parameters separated by "&" characters.

    Targeted search for open studies about the condition PTSD and the drug Fluoxetine on ClinicalTrials.gov:
    <a href="http://clinicaltrials.gov/search?recr=open&cond=PTSD&intr=Fluoxetine">open studies about the condition PTSD and the drug Fluoxetine</a>
This page last reviewed in May 2014