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HOLLIS User Guide

HOLLIS is the library's main search interface. It includes the Harvard library catalog as well as a huge (and more heterogeneous) collection of citations for a variety of materials, including articles and book chapters.

Refine My Results

Sort By

What does “relevance” mean? How is that calculated?

HOLLIS, like most databases, defaults to sorting results by something called “relevance.” Each database has its own proprietary formula, but generally, HOLLIS favors results that meet criteria such as: recent publication date; higher total number of matches to your search terms; matches to your search terms in the author, title, and subject fields; and, for articles, peer-reviewed or highly-cited articles.

"Resource Type," "Location," etc

HOLLIS allows you to filter your results to view a subset with specific features.

  • Select a filter name to apply that filter
  • Apply multiple filters by using the checkboxes and then selecting "apply filters" at the bottom of the screen
  • If a filter is cut off, hover your mouse over it to see the full name.
  • Pro tip: use the lock icon to keep a filter in place as you run a new search. Note that a locked filter will persist across tabs and sometimes across browser sessions.

Power Filters

Available only when searching Everything


This option---available via the toggle at the top of your search results, not in the "refine my results" menu---allows you to personalize the order of article results by discipline. It's especially helpful if your topic is difficult to capture in search keywords. Look for "personalize" at the top left of your search results. If you are signed in, HOLLIS will remember your choices.

Note: you may still see books in your results, but they will not be personalized.

Show only: Peer-reviewed articles

Limits to articles from journals designated as "peer reviewed" in Ulrichsweb: Global Serials Directory.

Resource type: Reviews

Limits to records that identify themselves as book reviews.

Resource type: Reference Entries

Limits to records that identify themselves as entries in handbooks, encyclopedias, etc.

Combine Filters

The relationship between filters depends on how you select them. The display under “Active filters” shows some, but not all, of the following relationships:

If you are using the checkboxes to apply multiple filters in a category such as author or location, you will see items from your original results that match any one of the applied filters for that category (OR relationship). Example: books OR articles about particle physics.

To create an AND relationship between filters from the same category, apply one filter at a time. Example: items on agriculture or farming that are in both Japanese AND Chinese.

There is always an AND relationship between filters from different categories. Example: items about particle physics that are books AND belong to Cabot Science Library.

Excluding a filter always creates an AND NOT relationship. (Use the red "x" to the right of the filter name to exclude.) Example: items on “ethics” that are archival or manuscript materials AND NOT dissertations.

Use Caution

Filters are drawn verbatim from the individual records in your search results, and they are only as good as the data they come from. Due to variations in HOLLIS records, you may see multiple versions of the same subject or author name, and you may encounter filters that look good but are very inconsistently applied. Selecting an inconsistently applied filter, or only one of the variations on a subject or author, will exclude all of the records that may be relevant but do not contain that exact entry for subject, author, etc.

It’s a good idea to select all variants of a relevant term. Often, the best strategy is to reformulate your search, using the language you see in the filter menus.

Near-identical filter options are particularly prevalent in "Everything," which bundles together records from many different sources, all of which may follow different conventions for, e.g., Shakespeare's name. Pro tip: you can see where the data comes from under "Record Source," at the bottom of the filter list.

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