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How to Search

National Guideline Clearinghouse™ (NGC™) provides you with two options for searching:

Basic Search

Detailed Search

Search Tips

Words entered this way:

Will be searched in a way that:

Diabetes Finds the word diabetes -- No variations
diabet* Finds the word diabetes, diabetic, and other word ending variations
"heart failure" Finds the exact phrase heart failure
diabetes AND pregnancy Finds the words diabetes and pregnancy anywhere in the guideline summary
colon OR colorectal Finds the word colon or the word colorectal, but not necessarily both

Boolean Operators

The NGC Search and Detailed search options support the use of the Boolean operators "AND", "OR" and "NOT"

AND

The Boolean operator "AND" narrows a search, retrieving only those guidelines containing at least one term from each concept. The AND operator is very good for narrowing a search to retrieve those guidelines most relevant to your topic.

OR

The Boolean operator OR broadens a search, retrieving all guidelines containing at least one of the search concepts entered, but not necessarily both. The OR operator is very good for linking synonyms or related concepts in order to retrieve as many relevant guidelines as possible.

NOT

The Boolean operator NOT excludes records from your search results. Be careful when you use NOT -- the term you do want may be present in an important way in guidelines that also contain the word you wish to avoid.

USING PARENTHESES

You can also use parentheses to construct your search strategies.

For example: entering the search expression -- (hip or knee) and arthroplasty -- will retrieve those guidelines containing the terms hip and arthroplasty or the terms knee and arthroplasty

WILDCARD/TRUNCATION

You can find plural forms of words or word-stems using the '*'. Asterisks can be placed at the start of a term or at the end or a term.

Automatic Concept Mapping

As appropriate, the NGC search engine attempts to map (match) the specified search terms/phrases against a standard table of disease/condition and treatment/intervention concepts derived from the U.S. National Library of Medicine's (NLM) Unified Medical Language System (UMLS)

If a match is found in the table, the NGC then searches for these terms in the Disease/Condition and/or Treatment/Intervention fields in the database.

If a match is not found in the table, the NGC searches the terms/phrases as a text word(s).

Here are some examples of how the concept mapping works:

Textword Searches

In addition to concept mapping, NGC will attempt to find the terms or phrases specified in your search query within the text of the NGC summary. If you are looking for a guideline related to a specific phrase, we recommend that you enclose your phrase in quotes.

Running your Search

Once you have entered your search criteria, click on the "Search" button to run the search.

search button image

The results will appear on your screen.

Sorting and Displaying Search Results

NGC will automatically return your search results sorted by relevance, with the most relevant guidelines listed first. This is derived through the use of a term-weighting algorithm.

An alternative option for sorting your search results by publication date is available through the Detailed Search.

From the search results page, you can either:

Frequently Asked Questions - Searching

Is NGC searching the complete, full-text guideline for my search terms?

Is the NGC search engine case sensitive?

My search returned a results page stating "no guidelines were found" -- Why doesn't NGC have any guidelines on my topic?