When handling search results in PubMed a user may encounter a situation when some operations are limited to a certain number of citations. While some users may think that, in practice, they will never need to deal with a very large number of citations, such situations do occur.

Below are instances when PubMed users will encounter a limit to the number of citations (and Pubmed messages alerting to that):

• When browsing a lengthy list of search results or jumping to a page towards the end of a search results list (This site can display up to 10,000 results. Please see the User Guide for more information on navigating your search results.)
  
• When saving citations to file (Only the first 10,000 citations will be saved in your file.)
  
• When e-mailing your citations (Only the first 1,000 citations will be sent in your email. You will receive citations in multiple emails.)
  
• When adding citations to a Collection in My NCBI account: (Only the first 1,000 citations will be added to collection.)
  
• When sending citations to Clipboard (Only the first 500 items will be sent to clipboard.)

These problems can be addressed with the following options:

• Divide the result set into smaller chunks using the results timeline or custom date range filter.
• Adjust your search to retrieve fewer results.

Other databases, such as Embase, CINAHL, Scopus, Web of Science, have similar, but not exactly the same maximums of the number of citations allowed for certain operations.