Once you have all of your database search results in Mendely, you can remove duplicates article citations. There are two ways to deduplicate.
Mendeley Deduplicate Tool
Go to the folder you would like to deduplicate in Mendeley Desktop.
Click on Tools from the top menu.
Choose Check for Duplicates.
Mendeley will scan your folder for duplicates. If a possible duplicate is found, Mendeley will display the duplicate citations and indicate the confidence that Mendeley has whether or not the two articles are duplicates. I
On the far right, there will be the option to Confirm Merge of the duplicates. If you are confident that the two are duplicates, then click Confirm Merge.
If you are not sure, you can click on the tiny triangle next to the title to see all the articles that Mendeley thinks are a duplicate and make your decision.
In Mendeley Desktop, go to your folder and click TITLE to arrange the citations by title.
Scan through the titles, looking for duplicate titles.
Right click, and Delete a duplicate citation.
This process can take longer depending on how many citations you have in your folder.
To check for duplicate references in your Mendeley library, select All Documents in the left-hand panel. Then, select Tools > Check for Duplicates from the menu bar.
A list of duplicate references will be displayed. Review the references and choose the details that you would like to keep from each reference by selecting the check box next to each field. Once you have reviewed all the field, click the Merge Documents button.