Your Choice of Database Determines What Type of Information You Will Find
When you decide to use one resource over another, you need to think about the capabilities of that resource. Some search resources are more specific than others.
Consumer Health Information sources target a certain audience and tend to be less science-intensive. they also tend to have simple search interfaces where using a single, representative word or two will be the best strategy for finding relevant information. However, you still need to keep in mind vocabulary differences, since some CHI resources may use "vaccines" while another might use "immunizations."
Google and other internet search engines tend to be very broad and will give results that encompass all audience levels and types of resource. Library databases tend to be much more specific. They may be centered around a particular topic or may contian only certain types of resources geared at a very specific audience.
Understanding these aspects of the database you are searching helps you set up a better search. If you are using Google, you know you will have to be more specific and detailed in your search in order to retrieve precise results tailored to the audience-level you need.
Using a library database that contains resources of only a specific topic may mean you don't have to worry as much about a complex search, but you do need to worry about the specific terms you use in your searches.
Your Choice of Database Determines How Complex Your Search Needs to Be
Keyword Search Databases
Most freely available resources that you use on the web are what we call "keyword" search databases. This type of database only recognizes the exact word you type in and searches for only that word in the text. In these datadases, using synonyms is very important, because you want to make sure you are searching for "heart attack" as well as "myocardial infarction" to find as much information of use as possible.
Google and Google Scholar are probably the two most popular keyword search databases, but any major search engine on the web searches by keyword as well. These resources require more complex searches to return thorough results. You need to think about using OR to combine similar words that both express the same idea, quotation marks to indicate that two or more words need to be in close proximity to each other, and possibly using NOT to exclude resources and narrow your results.
Theaurus-Based Databases
There are some special databases that allow you to search without a list of synonyms at your disposal. This is because they recognize a specialized set of terms that search all of the synonyms automatically. If you use PubMed, it uses a thesaurus called the Medical Subject Headings, or MeSH. If you use only MeSH terms (denoted by [mh] at the end of the word) to build a search in PubMed, it will automatically search all of the synonyms for that term, too.
To learn more about where to find MeSH terms in the thesauraus, read this section.
By telling PubMed to recognize MeSH terms and use them to search for an idea, you create less complex searches, but still return many relevant results. This is called concept searching because instead of looking for just a string of letters, the database is searching for all synonyms that represent the same idea as the MeSH term. For example, instead of searching:
"atkins diet" OR "low carbohydrate diet" OR "south beach diet"
you can just use the MeSH term that represents all of these synonyms: Diet, carbohydrate-restricted[mh]
By telling PubMed to search the MeSH heading of "Diet, carbohydrate-restricted[mh]" you are saying to find any article that is about this concept - no matter what they specifically call it.
It is important to remember two things:
- Only PubMed or PubMed Central can search by using Medical Subject Headings as concepts
- You have to tell PubMed that what you typed in is a subject heading by placing a [mh] immediately behind the term.
Concept searching allows you to create simpler searches than if you were using a keyword search database.