The help guides and documentation linked here will also answer basic search questions:
For example, if you type in "tylenol" the system will map to "acetaminophen" as the obvious correlated MeSH term. Or, if you enter a more general term such as "pregnancy" the Suggested Terms List will be much more comprehensive -- including all of the pregnancy-related MeSH terms. The examples below issustrate the process:
When using MeSH, be sure to choose the most specific MeSH term(s). For example, if you are searching for "arrhythmia," selecting the "heart diseases" subject heading would not be particularly effective because it's too broad. Try to find the subject heading(s) that best matches your particular topic or concept.
Click the checkbox to the left of one or more term(s) and follow the prompts. You may also want to click on the term itself to display the Tree Structure, which shows the MeSH terms family hierarchy and relationship to other potentially useful subject headings.
WHY CAN'T I "MAP" IN SOME DATABASES?
Some databases, like BIOETHICSLINE, don't have a controlled vocabulary or thesaurus in the Ovid system. In these cases, Ovid does not offer the Mapping feature. Instead, it searches verbatim for the keyword or phrase you entered on the Command Line.
In most databases, the search results will include citations with the word or phrase in the titles, abstracts, identifiers, and subject headings:
WHAT DOES IT MEAN TO "EXPLODE" A SEARCH TERM?
The Explode function searches for an index term (subject heading) and automatically ORs it with all of its narrower terms. In other words, when you activate the Explode function, you are searching for the subject heading you originally selected, PLUS all of the subject headings in its family hierarchy.
During Mapping, an Explode checkbox appears to the right of each MeSH term. Click the checkbox to explode the term. Results will be posted to a new set on the Main Search Page.
Exploding is important because documents are indexed (i.e., subject headings are assigned) using the most specific terms possible. So, a document about "endocarditis" would not also be indexed with the term "heart diseases." "heart diseases" would be too broad. Instead, articles on endocarditis would be indexed to the most specific subject heading -- "endocarditis". Your options would be to search for "endocarditis" as the subject heading, or to explode "heart diseases" to retrieve "endocarditis" plus all the other related subjects in the "heart diseases" tree structure.
Rule-of-Thumb: Be sure to use Explode for comprehensive searching.
HOW DO I VIEW THE FAMILY HIERARCHY OR TREE STRUCTURE FOR A SUBJECT HEADING?
During the Mapping process, you can click on any term that appears on the Mapping Page to view its complete hierarchy. From the Tree Structure page, you can select subject headings or apply the Explode function.
HOW DO I USE SUBHEADINGS?
If you are using MEDLINE, CINAHL, or HEALTHSTAR, which all contain a subject heading Mapping feature, you will automatically be presented with a Subheadings Selection Page during the Mapping process. Subheadings can be attached to a subject to make it more specific and relevant to your search.
For example, if you are searching for "surgical treatments for a ruptured spleen," you can attach the "surgery" subheading to the "spleen" subject. Or, if you are searching for "prevention of HIV in the latino population," you can attach the "prevention and control" subheading to the "hiv infections" subject heading.
You may select one or more appropriate subheadings by checking on the box next to each term. If you do not check any particular subheading(s), the system will actually search for all of them.
A common mistake made by MEDLINE searchers is to over-use subheadings. This means that searchers have a tendency to check subheadings too frequently. Because subheadings specify a particular aspect of a topic, they effectively reduce the number of citations you retrieve. If you find that you are finding too little information, you may be over-using the subheadings.
Rule-of-Thumb: Only select subheading(s) if you are certain that you want to limit the retrieval to the few citations that match the specific subheadings you have selected.
WHAT DOES THE FORWARD SLASH / MEAN IN A SEARCH STATEMENT?
The forward slash / means that the term is a valid controlled vocabulary term which has been searched in the Subject Headings field of the database.
If there are no subheading abbreviations after the forward slash /, that means that you have selected ALL subheadings. But if there are subheading abbreviations after the forward slash /, that means that you have selected subheadings. For example, if you see:
WHAT DOES THE ASTERISK * MEAN IN A SEARCH STATEMENT?
The asterisk * means that when you were going through the Mapping process, you selected the "Focus" option. Selecting the "Focus" option tells the system that the retrieved citations should include your subject heading as a major focus of the articles. If you do not select the "Focus" option, you will retrieve all of the citations in which your subject heading is a major focus AND a minor focus.
In other words, the "Focus" means that you want your subject heading to be emphasized in the articles. Selecting "Focus" retrieves fewer, more precise citations; while not selecting "Focus" retrieves more, less precise citations.
For example, if you see:
WHAT DOES THE "EXP" MEAN IN A SEARCH STATEMENT?
The "exp" means that you have "exploded" the subject heading. See a more detailed explanation of the "Explode" function
.For example, if you see:
The "exp" indicates that you have selected the "heart diseases" subject heading, along with all of the narrower subject headings in its tree hierarchy.
HOW DO I SEARCH FOR AUTHORS IF I ONLY KNOW THEIR LAST NAMES?
Author searching is most effective if you know the person's last name, and first and middle initials. When articles are indexed in MEDLINE, the author's name, Stanley J. Bernard, is translated to Bernard SJ. So, to find articles by this particular individual, you would ideally need to know his first and middle initials.
However, it is not necessary to know the first and middle initials in order to search for an author. When you invoke the "Author" feature from the Icon Bar, Ovid will prompt you with instructions on how to search the author field. Enter as much of the author's last name as you know. Ovid will display the author index, listing the names which most closely match the name you entered. You may then choose from among the displayed names.
Command-level Search Syntax -- called Direct Entry -- can also be used. Enter the author's last name on the "enter subject" prompt. (Click here for more information on using direct entry commands to bypass menu options.)
On the example below, notice that the author's missing initials are replaced by the dollar sign -- $. This is called "Truncation":
| Retrieves all articles written by any author whose surname is Bernard, regardless of the author's first name & initials. This search would retrieve articles by Audrey Bernard, Brendan James Bernard, Cathleen Bernard, Doris Ann Bernard, Ethan L. Bernard, etc. | |
| Retrieves all articles written by S. Bernard, regardless of the middle initial. This search would retrieve articles by Selma J. Bernard, Sylvia Garland Bernard, Samuel Bernard, Stanley F. Bernard, etc. |
| Retrieves all articles written by Thomas E. Starzl. | |
| Retrieves all articles written by Thomas Starzl. This strategy does NOT retrieve articles by Thomas E. Starzl, however, because no truncation symbol was used for the middle initial. | |
| Retrieves all articles written by Thomas Starzl, regardless of whether he used his middle initial when publishing. | |
| Retrieves articles by Starzl, regardless of the first name and middle initials used. If you knew that a Dr. Starzl had published a number of articles about transplantation, but didn't know that the doctor's name is Thomas, you could use the truncation symbol in place of the first and middle names. |
WHAT IS THE DIFFERENCE BETWEEN "TEXTWORD" AND "SUBJECT" SEARCHING?
"Textword" searching looks for a word or phrase in the titles or abstracts of the articles. It's called "textword" searching because it searches the original text -- titles and abstracts -- of the articles. "Subject" searching looks for controlled vocabulary terms (i.e., MeSH) that have been assigned to represent each article's subject content.
Subject searching is more precise than textword searching because subject searching guarantees continuity of language and terminology. It also allows you to manipulate the subject by indicating whether to explode, what subheadings to select, etc.
Consider this example: If you are looking for information on HIV and AIDS, the appropriate way to approach the topic is to explode the "hiv infections" subject heading. This will retrieve articles that are indexed to HIV, AIDS, the AIDS-related complexes, and so on.
But if you are searching for HIV/AIDS as a textword, you'll have to guess at what terminology the authors have used in writing the titles and abstracts. If you do a textword search for "HIV," you'll miss all of the articles that say "AIDS". If you do a subject search for "AIDS," you'll miss all of the articles that say "HIV," "acquired immunodeficiency syndrome," and "acquired immune defficiency syndrome." In other words, textword searching runs the risk of missing potentially useful literature.
HOW DO I LEARN MORE ABOUT A DATABASE?
Information about the scope and coverage of each database can be found on the "Choose a Database Page. " Go to this menu by clicking on the "change databases" option. Then click on the "I" icon located next to the database name.
