Keyword search

Search engines, like Google, search by keyword. The default search in Orbis, Quicksearch, and Articles+ is also by keyword, where you will get results with your keyword(s) located anywhere in the record or document.

Subject search

A subject defines a book or an article as a whole, and subject headings link information -- just like how hashtags link conversations in social media (#yalelibrary). Using subject headings is an effective way of doing research.

Ways to identify library subject headings:

1. Start with a keyword search in Orbis or Quicksearch, and identify 2 or 3 books that are loosely related to your topic (they don't have to be perfect, just close enough). Open the records and look at the "Subject" field -- voila! Write these subjects down, or click on them (they're hyperlinked!) to uncover other material within that same subject.
2. Some resources will offer the ability to browse subjects, for example:

• ​in Orbis, select "Subject Browse" in the dropdown menu from Orbis Basic Search
• in the database Academic Search Premier, select "Subject Terms" in the top toolbar 

1. Individual databases have their own thesauri for controlled vocabulary. Browse or search these thesauri to find the "correct" version of words and phrases used as subjects, which you can then apply to your search.

Combine search terms

You can combine your keyword and subject searches by using Boolean operators AND, OR, NOT in an Advanced Search. When combined with keywords and/or subjects, boolean operators will help focus your search in the following ways:

• AND will narrow your search, requiring all search terms be present in results
• OR will retrieve variations ("pets" or "dogs" or "pugs"), so at least one term (maybe more) is present in results
• NOT will exclude items from your search, helping to narrow results to only relevant information

In the example above:

• cats OR dogs will return results where either cats or dogs are mentioned
• cats AND dogs will return results only when both cats and dogs are mentioned
• cats NOT dogs will returns results when only cats are mentioned