Keywords:
The search terms or keywords you use to search are what determine the results you get.
1. Express your topic in a topic sentence
2. Generate keyword search terms by identifying the main ideas or concepts within that topic sentence:
3. Expand your search terms by brainstorming related terms or synonyms that describe your main ideas
Boolean Operators or Combine Search Terms; AND, OR, NOT
Boolean logic is a building block of many computer applications and is an important concept in database searching. Using the correct Boolean operator can make all the difference in a successful search.For example, if your search terms are Shingles and vaccines and aged.
- AND searches find all of the search terms. For example, searching on shingles AND vaccine AND aged returns only results that contain all three search terms. Very limited results.
- OR searches find one term or the other. Searching on Shingles OR Varicella-Zoster OR chickenpox returns all items that contain any of the three search terms. Returns a large number of results.
- NOT eliminates items that contain the specified term. Searching on Shingles NOT chickenpox returns items that are about Shingles, but will specifically NOT return items that contain the word chickenpox. This is a way to fine-tune results. Note: sometimes AND NOT is used; serves the same function as NOT.
Using Boolean Search with Exact Phrases:
If you're searching for a phrase rather than just a single word, you can group the words together with quotation marks. Searching on "Varicella Zoster" will return only items with that exact phrase.
Phrase Searching:
If you are searching for a phrase, keep in mind that not all databases will search multiple words automatically as a phrase. Check the database Help pages to be sure how that database handles multiple works.
- 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.
- Some databases such as PubMed (and Google) use " " around multiple words to designate a phrase search. For example: "Varicella-Zoster Virus"
When to use parentheses:
Think of your search in concepts, then put those concepts inside parentheses. Different databases have different rules about combining searches. To make sure you get the search you want, use parentheses - every database follows those rules.
Truncation:
Using truncation symbols allows you to expand your results by including various endings for a search term. Most databases will designate a non-alphabetical symbol -- like ! , *, or ? -- as a truncation symbol; check the database Help screens to find out the specific symbol. PubMed uses an Asterisk ( * ). Using the truncation symbol at the end of the root word will bring back results that include any ending of that root word. For example, if the truncation symbol was a ? , then:
- child* = child, child's, children, childish, childlike, childhood
- transplant* = transplants, transplantation, transplanted