Free Text Search

The most simple search involves a free text search. This is based on a word or phrase of your choice appearing anywhere in the source material. Most bibliographic databases have their own individual controlled language which is composed of keywords. These are organised in a structured hierarchy (Thesaurus). This demonstrates the relationship between them, and enables the user to include all the terms that are relevant to their search. The Thesaurus permits a more controlled and detailed search to be undertaken because keywords are used in the indexing of the database.

Boolean Logic

If the only thing you learn about effective searching is how to use Boolean logic, you will not go far wrong. Boolean logic breaks a subject down into concepts and uses “operators” such as:

AND – narrows down a search using a combination of terms
OR – broadens a search by searching for a number of different terms
NOT – narrows down a search by eliminating terms that are not associated with something you are trying to find

For example:

• Salmonella AND eggs will retrieve records that contain both terms
• Salmonella OR eggs will retrieve all records containing a reference to either salmonella or eggs
• Salmonella NOT eggs will retrieve records that contain Salmonella but have no reference to eggs

Boolean logic can be improved by “nesting” which involves the use of parentheses to combine several search requests, for example:

• (Salmonella OR Listeria) AND (chocolate OR eggs) will retrieve records on Salmonella and eggs, Salmonella and chocolate, Listeria and eggs, and Listeria and chocolate.

Not all search engines support Boolean logic but most academic resources (journals, bibliographic databases, reference works) will.

Some search engines will support phrase searching which looks for a specifc term. For example:

• “salmonella in eggs” will only find records with that exact term.

Proximity

Not all search engines recognise proximity operators but a few search engines will have advanced features where proximity searching can be deployed. The most common proximity operator is “NEAR” allowing you to specify two terms that can be found close together.

Wildcards

Wildcards are not supported by all search engines but can be used to represent a character or number of characters. They are useful when you are either not sure how to spell something or when you want to find records with different word endings. Different search engines use different symbols but the most common wildcards are “*” and “?”. for example:

• poison* will retrieve all records that include poison, poisons, poisoned or poisoning
• col*r will retrieve all records that contain either colour or color
• wom*n will retrieve all records that contain either woman or women

Field Searching

Other search tools

Depending on the database or information resource you are using, you may be able to refine your search, save your search, set up search alerts which will run a search for you and email you the results on a regular basis.

Search tools and user guides can be found either on your library website or may be made available by the resource provider. These are well worth using in order to get the most out of your searching.