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Using the Library of Congress Online: A Guide for Middle and High School Students

Search Strategies

There are several approaches and strategies to employ when doing online research using the Library of Congress website. Starting with the single search box, found on the Library of Congress website, you will discover digital primary sources as well as research tools and guides created by librarians. Use the tabs below to learn more about how to search the Library's website, expand your search to include databases and online catalogs, and evaluate the results of your research.

If you need additional support related to developing search strategies, you might want to explore the “Guide to Student Research and Historical Argumentation” External, a resource developed by National History Day and the Library of Congress to help support students in the historical research process.

Decide Where to Start

Knowing where and what to search are just as important as understanding how to search; deciding where to start may depend on the topic you are investigating and on the kind of information you are looking for. Are you looking for historical newspapers, directories, journal articles... the answers to these questions will inform where you search.

  • Books: use the Library of Congress Online Catalog
  • Journal Articles: browse through the general resources listed on the E-Resources Online Catalog. Please note: e-resources marked ON-SITE ONLY cannot be accessed outside of the Library of Congress. For e-resources that can be accessed offsite, look for the FREE ACCESS designation.
  • Subject/Topics: browse resources through the subject listings on the E-Resources Online Catalog landing page, or refer to our collection of Research Guides for more specific direction.

Access Specific Types of E-Resources

Research Using Keywords


A significant word or phrase in the title, subject headings (descriptors), contents note, abstract, or text of a record in an online catalog or bibliographic database that can be used as a search term in a free-text search to retrieve all the records containing it. Most online catalogs and bibliographic databases include an option that allows the user to type words that describe the research topic (in any order) and retrieve records containing the search terms in the data fields the system is designed to search whenever the keywords option is selected. One disadvantage of a keywords search is that it does not take into account the meaning of the words used as input, so if a term has more than one meaning, irrelevant records (false drops) may be retrieved.

Reitz, Joan M. Online dictionary for library and information science: ODLIS. 1996. [Westport, Conn.]: Libraries Unlimited.

The keyword you select for your search should describe important aspects of your investigation, therefore, selecting the appropriate keyword(s) for your search is the foundation for your research. Despite their various algorithms and filters, databases, search engines, indexes, and even catalogs work by matching your keywords to their records, this is how you get search results. The more keywords these search tools can find, the more relevant the results will be for your search. The search will only give you back what you tell it you are looking for, so selecting those keywords and related or synonymous terms, is important. For example, if you are researching teenagers and their reading habits, you want to make sure your keywords include — teen, teens, teenager, youth, young adults, and depending on the page you want to target, even — child, children, kids, etc.

Students from Sussex Academy in Delaware conduct research in the Science, Technology and Business Division Reading Room. February 8, 2019. Photo by Shawn Miller, Library of Congress Office of Communications.

Use Keywords to Develop Your Topic

Deciding on a topic you'd like to write about and defining the parameters of your research is one of the most challenging and important aspects of the research process.

When deciding upon a topic, remember these three rules:

  1. Decide the area you are interested in writing about (ex: global warming)
  2. Define the topic you wish to research (ex: effects of global warming on children)
  3. Refine the topic area so that the topic is manageable - neither too large nor too small (ex: effects of global warming on children in New Zealand where the ozone is the weakest)

Need help choosing a topic?

Try browsing through these resources to help you develop some ideas:

Searching the Library of Congress Website (

Use the Search Box on

You can search by typing a keyword into the search box, and you can also search for a specific type of item—e.g., map, audio recording, or manuscript (handwritten document)

  • Tip: If you’re searching on a specific topic (for example, the American Revolution), it may be helpful to come up with a list of related terms (e.g., Alexander Hamilton, George Washington, King George III, Yorktown, Bunker Hill), and try searching with those, too.
  • Tip: As you brainstorm search terms, consider how terminology may have changed over time. Words that are used today may not have been used historically, and vice versa.
Location of the search box on

View, Sort or Filter Results

There are a number of ways to view your search results (e.g., list view, gallery view, grid view etc.). It is also possible to sort, or re-sort, your search results by date or title. You can also narrow your search results using filters for year, subject, language, and more.

Ways to display search results on

Explore "About this Item" for Digitized Primary Sources

On, each item generally has a record that includes details like title, date created, creator, and more. There are also clickable details that link to similar items and related materials that can help expand your research. On this page, you can also learn about copyright restrictions related to the item. If you have questions about copyright, check out the section in this guide on “Citations and Formatting.”

About this item page on

Search the Library of Congress Online Catalog

The Library of Congress Online Catalog is available at It is the primary search tool for discovering all types of materials in the Library's print and online collections. Search results will provide full bibliographic information for each collection item along with the location and call number needed to request and use that item at the Library. If the material is digitized, there will be a link to the primary source online.

There are several ways to search the online catalog. The instructions below focus on the Advanced Search option.

  1. Select Advanced Search from the "Search Options" drop-down menu
  2. Enter your search term(s) in the "Search" box(es). Please note:
    • Capitalization does not matter.
    • Use a percent sign ( % ) as a single-character wildcard, either inside or at the end of a search word: wom%n
      Note: If your search term contains a percent sign, remove the %. Enter 5% Nation as 5 Nation
    • Use a question mark ( ? ) for truncation (different forms of a root word) and as a multiple-character wildcard, either inside or at the end of a search word: strong>entrepr? or col?r
    • Most punctuation marks (hyphens, slashes, periods, etc.) are replaced by spaces. Because spaces are used to divide words, remove hyphens from ISBN but not ISSN number searches. Enter 0394487249 for ISBN 0-394-48724-9, but enter 0028-7806 for ISSN 0028-7806
  3. Select all of these, ;any of these, or as a phrase from the drop-down list to specify how you want multiple words to be combined.
  4. Narrow the scope of your search by changing Keyword Anywhere (GKEY) to the index of your choice in the next drop-down list (after within).
  5. Add to your search by selecting a Boolean operator (AND, OR, NOT) and entering more search terms.
  6. Refine your search by adding limits.

Search Strategies for E-Resources

Developing a search strategy can help to narrow down your results lists and replicate a consistent search across multiple e-resources/databases.

  • Break your research topic into keywords.
    • Look for the independent concepts that might make up your research topic
    • Try the thesaurus or subject headings to help you look for discipline-specific terms/controlled vocabulary
  • Combine your keywords/search terms with Boolean operators
    • OR (synonyms: any of these words, good for related terms/concepts)
    • AND (restrict: all these words)
    • NOT (eliminate these words completely, the most restrictive search technique)
  • Use parentheses with your terms and Boolean operators to create your search phrase
    • i.e., (cat OR kitten) AND (wild OR feral OR homeless)
  • Determine your conditions and apply them to your search as limits or filters
    • i.e., publication year, document type, or Peer Reviewed
  • Place quotation marks (“ ”) around phrases to keep words together.
    • Use this for an exact quote, phrase or order of the search term.
      • i.e., "latin america"
  • Add asterisks (*) to “fill-in-the-blank” at the end of a word - it acts as a "wild card"; The asterisk will be replaced by any applicable letters
    • This is called truncation
    • You can use asterisks as a shortcut for OR-ing words that have identical roots
    • i.e., paint* will search for paint, painting, painters, painterly, etc.

How to Evaluate Your Research Results

Throughout the process of conducting your research, you will find yourself pausing to reflect, evaluate, and refine your results and research.

You may need to repeat this process across a number of collections, subject areas, catalogs, and/or databases in order to get the exact type of results you are looking for.

Remember, when using the Internet for research, it's important to evaluate the accuracy and authority of the information you find on websites. Search engines, like Google, find sites and pages of all levels of quality. Try to keep these things in mind when deciding if a web page is reliable and appropriate for your research:

  • authority/credibility: Is the author listed? If so, can you determine the author's credentials and expertise?
  • accuracy/verifiability: Has the author cited their sources and provided ways to verify data points or claims?
  • bias/objectivity: Does the author or website consider counterarguments?
  • currency/timeliness: How recent is the publication? Does it draw on other recent writings and scholarship?
  • scope/depth: Does the publication show depth of research, information, or perspective?
  • intended audience/purpose: What is the purpose of the website or publication? To inform, persuade, or other? Who is this source for?

Research Tips!

  • Take advantage of features within databases to help you sift through the results and refine your search, making your research more manageable, tools and features might include: subject headings, tags, related searches, etc.
  • Look around for icons to: print/email/save articles and/or sea rches, citation generators to help you cite what you've found
  • Use a variety of resources and databases, don't be satisfied with the results of just one tool