The latest version of PubMed has made a significant change behind the scenes that for more sophisticated PubMed users, needs to be addressed. If a PubMed user manually types in a subject heading, a MeSH term, in the search box, double quotation marks should now be used around these terms even with the [MeSH], [MH], or [Majr] fields; otherwise PubMed will automatically map to a variety of Mesh terms.

There can be times when PubMed’s mapping of [Mesh] designated terms can be useful. If, for instance, you knew that the Mesh term for cancer was neoplasm, but did not make it plural, using double quotation marks would retrieve no results while not using quotation marks would retrieve relevant results as PubMed is able to map to the correct Mesh term.

Even though manually typing in Mesh terms into the search bar can be more efficient, it can also become problematic. It is advised to simply use the MeSH Database to not only ensure that you are inputting the terms properly, but also to ensure that you are using the correct term for the concept you are searching for!

Sometimes just combining search terms (keywords) with the standard Boolean ‘AND’ operator is not granular enough to focus results in to retrieve relevant articles. Typically, in addition to Boolean Operators and double quotes for exact phrases, many databases also allow specifying that the keywords searched be within a certain number of words of each other in either direction. This bridge between the narrow exact phrase search and the broad ‘AND’ operator search is called Proximity or Adjacency searching and it uses Proximity, or Adjacency, operators. Proximity searching is not applicable to searching with subject headings, it is applicable to keyword searching only. Proximity operators help increasing specificity of the search. Typically, in complex search strategies, both Proximity and Boolean operators are used.

Proximity searching is available in major proprietary databases, including Embase, Scopus, CINAHL, Web of Science, and databases on OVID platform, such as Medline and PsycINFO. Proximity searching is not available in Pubmed.

Proximity operators and rules for using them vary by database.

An example of Proximity Operators in Embase:

The databases specific Proximity Operators and the rules for their use can be found in the Help pages for each database.

Explore the MSK Library’s redesigned A-Z Databases list!

Last year our old alphabetical database list got a makeover and now it’s easy to search and browse for the perfect database for your specific needs.

Our databases can always be browsed alphabetically, but now they can also be browsed by subject area and found by keyword search!

Once you identify the database you want to search, the link will take you directly to that database – remember, if you are working remotely be sure to log into Remote Access first – or you can “share” the database by selecting the icon, which allows you to copy the permalink to the database as well as send the URL to yours or someone else’s email.

The Database page is linked to the Help page but you can always contact the Library with questions about this page as well as for assistance with database selection and searching.