This year the National Library of Medicine (NLM) is transitioning the process of MeSH indexing in PubMed from manual to automated.

MeSH (Medical Subject Headings) are assigned to MEDLINE citations for the purposes of enriching the metadata and increasing discoverability.

Until 2022 MeSH indexing was done by human indexers at the National Library of Medicine. Starting 2022 human indexers will only oversee and troubleshoot MeSH indexing.

One of the major benefits of automating the process of MeSH indexing is almost instant appearance of MeSH in MEDLINE citations in PubMed. With manual indexing this was delayed for a few months on average. Citations awaiting MeSH indexing were called In Process citations which could be found by keyword searches only.

The downside of automated MeSH indexing, at least in the beginning, could be, potentially, increase in indexing errors. The NLM will be engaged in the ongoing improvement of MeSH indexing algorithm.

Read more about the transition.

Starting on March 14th, PubMed Central (PMC) will be launching their new PMC website. The new interface will resemble the recently updated PubMed interface in 2020. This update is the first of ongoing updates to PMC to modernize it to provide a quicker more responsive website.

If you would like to explore the new interface before it goes live, check out PMC Labs.

For more information about the new website, you can check out the NCBI Insights blog post: Updated PMC Launching Soon!

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.