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ECON 2120 - A. Bledsoe: Keywords & Search Statements

A library research guide for microeconomics

Search Strategies

Searching for articles and books in the library requires skill, practice, and patience!  If you only use the internet for resources, you are missing carefully chosen collections of high-quality information provided by the library through the catalog and databases.  Although these sources are found using an internet connection, you are not searching the Web (WWW).  The catalog and databases contain information that is not found on the internet, that is high quality, that is accessible 24/7, and it is what your professor is wanting to see in your essays! 

The skills needed for searching the catalog and databases are identifying keywords and understanding Boolean operators.

Identifying keywords

Keywords are the words you type into a search box to search for information on your topic.The words you use to describe your topic may be different from the words used in the library catalog and databases. We use natural language in conversations and searching the internet for information, but the library uses a controlled vocabulary for searching the catalog and databases. You can use keywords to find out the actual subject heading of your topic. For example, people recognize that WWII is commonly known as World War II, but in the catalog and databases the actual subject heading is World War (1939-1945). Once you discover the subject heading, use that term to locate more resources on that specific topic. 

Example topic: Paper Waste

Combine keywords and subject headings to narrow your topic. If you do a search in the library catalog for trash, you will find hundreds of books that have that word somewhere in the record but will not necessary be about paper trash. To locate more relevant sources, use the keywords paper waste AND recycling to narrow your search to books that discuss those two concepts.

Check out this tutorial from the Leonard Lief Library at Lehman College CUNY.

Boolean Search Techniques

Boolean Search TechniquesBoolean Operators (also referred to as logical operators or connectors) are words used to connect your search terms. Use these search techniques to either narrow or expand your search in a database.

AND: The operator AND will retrieve search results that contain all of the search terms used.  Use AND to narrow your search by retrieving more specific results.

OR: The operator OR will retrieve search results that contain any of the search terms used. Use OR to expand your search by broadening the range of resources. OR is most useful when using synonyms as search terms.

NOT: The operator NOT will eliminate search results that contain a search term. Use NOT to narrow your results by excluding resources with a particular search term.



Database Search Tips

  • The key to being a savvy online searcher is to use common search techniques that you can apply to almost any database, including article databases, online catalogs and even commercial search engines.

  • This is important because searching library databases is a bit different from searching Google.

  • The techniques described in this section will enable you to quickly retrieve relevant information from the thousands of records in a database.

What is a database?

According to Encyclopedia Britannicadatabase, also called electronic database, is a collection of data, or information, specially organized for rapid search and retrieval by a computer

A library database is a searchable electronic index of published, reliable resources. Databases provide access to research materials from academic journals, newspapers, and magazines. Some databases also include e-books, relevant Web resources, and various multimedia.

For more information on databases, see What is a Database and How do I use it?


What to look for:

Boolean operators form the basis of mathematical sets and database logic.          

  • They connect your search words together to either narrow or broaden your set of results.

  •   The three basic boolean operators are: AND, OR, and NOT.

  Why use Boolean operators?

  • To focus a search, particularly when your topic contains multiple search terms.

  • To connect various pieces of information to find exactly what you're looking for.

  • Example:
    second creation (title) AND wilmut and campbell (author) AND 2000 (year)

Search Order:

Databases follow commands you type in and return results based on those commands. Be aware of the logical order in which words are connected when using Boolean operators: 

  • Databases usually recognize AND as the primary operator, and will connect concepts with AND together first.

  • If you use a combination of AND and OR operators in a search, enclose the words to be "ORed" together in parentheses.


  • ethics AND (cloning OR reproductive techniques)
  • (ethic* OR moral*) AND (bioengineering OR cloning)


What to look for:

  • Root words that have multiple endings. Example: sun = suns, sunshine, sunny, sunlight

  • Words that are spelled differently, but mean the same thing. Example: color, colour

  • Truncation/wildcard symbols vary by database. Check the help screens to find out which symbols are used.


Truncation, also called stemming, is a technique that broadens your search to include various word endings and spellings.

  • To use truncation, enter the root of a word and put the truncation symbol at the end.

  • The database will return results that include any ending of that root word.

  • Examples:
    child* = child, childs, children, childrens, childhood                                                                  
    genetic* = genetic, genetics, genetically                                                                     

  • Truncation symbols may vary by database; common symbols include: *, !, ?, or #   


Similar to truncation, wildcards substitute a symbol for one letter of a word.

  • This is useful if a word is spelled in different ways, but still has the same meaning.

  • Examples:
    wom!n = woman, women
    colo?r = color, colour

What to look for:

To find subject headings for your topic:

  • Look to see if the database has an online thesaurus to browse for subjects that match your topic (check the Help screens).

  • Some databases publish thesauri in print (e.g. Thesaurus of Psychological Index Terms for the PsycInfo database).

Another way to find subject headings:

  • Start with a keyword search, using words/phrases that describe your topic.

  • Browse the results; choose 2 or 3 that are relevant.

  • Look at the Subject or Descriptor field and note the terms used (write them down).

  • Redo your search using those terms.

  • Your results will be more precise than your initial keyword search.


What are subject headings and keywords?

Subject headings:

Describe the content of each item in a database. Use these headings to find relevant items on the same topic.  Searching by subject headings (a.k.a. descriptors) is the most precise way to search article databases.

It is not easy to guess which subject headings are used in a given database. For example, the phone book's Yellow Pages use subject headings. If you look for "Movie Theatres" you will find nothing, as they are listed under the subject heading "Theatres - Movies."

Keyword searching:

Is how you typically search web search engines. Think of important words or phrases and type them in to get results.

Here are some key points about each type of search:


          Keywords         vs.       Subjects      
  • natural language words describing your topic - good to start with
  • pre-defined "controlled vocabulary" words used to describe the content of each item (book, journal article) in a database
  • more flexible to search by - can combine together in many ways
  • less flexible to search by - need to know the exact controlled vocabulary term
  • database looks for keywords anywhere in the record - not necessarily connected together
  • database looks for subjects only in the subject heading or descriptor field, where the most relevant words appear
  • may yield too many or too few results
  • if too many results - also uses subheadings to focus on one aspect of the broader subject
  • may yield many irrelevant results
  • results usually very relevant to the topic


Youtube video that explains the differences between keywords and subject headings.  


What to look for:

Records in library databases are comprised of fields containing specific pieces of bibliographic information. Common fields include:

  • author

  • title

  • journal title

  • abstract

  • publisher

  • date/year of publication

  • subject/descriptor


How database fields improve your search.

  • Limiting your search to specific database fields can yield more precise results.

  • For instance, if you are looking for articles by Elon Musk instead of about him, it is more efficient to limit your search to the author field.

  • To find various fields within a database, look for drop down boxes or menus to select the field you want to search.

  • Then combine words and fields together with boolean or proximity operators, depending on how precise you want to be.




  • If you do not choose a specific field, the database usually reverts to a keyword search, where your words will be searched throughout the record.

  • If your keyword search retrieves too many records (more than 50), try narrowing your search to retrieve a more manageable result.

  • Information overload - too many results - can be a worse situation than finding only 10 very relevant results.


Examples of fields:

The record below shows the field names on the left: Title,  Author, Source, Subject Terms, Abstract, etc.



What to look for:

  • Different databases interpret searches differently. A common variation is how databases recognize phrases.

  • Some assume that words typed next to each other should be searched as phrases.

  • Others automatically put a Boolean AND between your search terms, requiring that all the words be present, but not necessarily adjacent to each other.

  • These searches can retrieve very different results.


Phrase Searching Tips:

Most databases allow you to specify that adjacent words be searched as phrases.

  • Using parentheses or quotes around search words is a common way to do phrase searching, but not all databases or search engines use them.

  • Example:  "genetic engineering"

  • Hint: It is often very easy to do phrase searching from the Advanced or Guided search in a database.



Proximity Operators:

  • Many databases allow you to specify that the words you are searching are within a certain proximity of each other.

  • Proximity operators are more specific than Boolean operators and make your search more precise.


Proximity Operator Examples:

Proximity operators also vary by database, but some common ones include:

w# = with

  • With specifies that words appear in the order you type them in.

  • Substitute the # with a number of words that may appear in between. If no number is given, then it specifies an exact phrase.

  • Examples:
    genetic w engineering (searches the phrase genetic engineering)
    Hillary w2 Clinton (retrieves Hillary Clinton, Hillary Rodham Clinton, etc.)

n# = near

  • Near specifies that the words may appear in any order.

  • Substitute the # with a number of words that may appear in between.

  • Examples:
    cloning n3 human (retrieves cloning of humans, human cloning etc.)

Consult the database Help screens to find out how to search by phrases or to specify proximity. 

What to look for:

Stop words are frequently occurring, insignificant words that appear in a database record, article or web page.

Common stop words include:

  • a

  • an

  • the

  • in

  • of

  • on

  • are

  • be

  • if

  • into

  • which


About Stop Words:

Why should you care about stop words?

  • Many databases ignore common words from your search statement.  If included, the database returns far too many results.

  • So you know which words to exclude from your search statement.

  • To make sure they are included if they are a significant part of your search.

  • Many databases recognize common stop words when they are part of the controlled vocabulary of subject headings and descriptors.  Example: balance of payments

  • Stop words vary by database. Check the Help screens for a list.

How can you avoid using stop words in your search?

In some databases, you can use techniques to include stop words as part of the sear

  • Some databases use quotes around stop words.  Example: Title keyword= out "of" Africa retrieves title: Out of Africa

  • Choose the most significant words that describe your topic and connect them together using Boolean operators or proximity operators.

  • Search for your terms in specific fields, such as author, title or subject/descriptor.

The information for Database Search Tips was authored by Tina Chan at Massachusetts Institute of Technology, borrowed and adapted with permission by Nikki Crane, Taft College Library,  May 21, 2019.