Search technique
When you are searching a database with one search term you will often get a large number of search results. Even so many they become unmanageable to work through. You must then limit the search by adding more search terms, i.e. search for several terms at once.
Boolean operators
To limit the number of search results in a database search you use so called Boolean operators. They are AND, OR and NOT. In this illustration you can see how they work. The use of these operators depends on if the database supports them and how they are used. Because there is no standard for their use, you must find out how they work in the database you are currently using. Always study the help pages if you are not sure how the operators are used in a database. In many databases AND is automatically added between terms when you are entering several search terms in one field, e.g. in our own library catalogue. If you search for:
Management and leadership
Management leadership
The results are the same. Try this yourself in the library catalogue.
Crib
You must remember that AND is treated very differently in various databases and search engines, e.g. some use the plus sign + to mark AND. Click here for a list of operators used in different databases.
Phrase search
In some situations it can be practical to perform so called phrase searches. If you search for the title Truth or dare in the catalogue, you will get a result list that contain either of these words, but not necessarily both. If instead you search for “Truth or dare” with quotation marks you will get exactly that title. Then you have made a phrase search. The operator OR looses its function and is treated like any word in a title. In many databases quotation marks are used to mark phrase searches.
Truncation
Sometimes a search term can be too limiting by not including variants of endings. In that situation you need to truncate the word by shortening it and ending it with an asterisk*. If for example you are searching for astron* you will get the variants of astronaut, astronomer, astronomy etc.
Masking
Similarly you can mask letters to include spelling variants in the same search. It can also be used if you are not sure about the spelling of a term. Colo*r will retrieve documents with both British and American spellings, color and colour. Different signs are used for this function, e.g. *,? or $. Check the help pages of the database for the correct use.
Proximity operators
In some, more advanced databases, there is the possibility to use so called proximity operators. They can differ a little, but common variant are ADJ, NEAR and WITH. You need to check which operators are supported in the database you are searching. If for instance you are searching the medical database Medline for the disease diabetes mellitus and you enter diabetes adj mellitus you have stated that the words diabetes and mellitus should be placed next to each other in that order in the retrieved records.
Diabetes adj mellitus
Proximity operators in Medline
Adj (Adjacent)
Retrieves references where the search terms are next to each other in the given order.
Near
Retrieves references where the search terms are in the same sentence, but in any order.
With (Within)
Retrieves references where the search terms are in the same field, but in any order.
Try different search techniques:
Kent Pettersson
2005-06-22
