Once you have thought about your keywords there are a few techniques to use which will help you create a comprehensive but relevant search.
These include:
See the guidance below on how to apply these techniques to create a comprehensive search for your topic.
Although databases are developing to automatically search for variant spellings, they might just search for the exact letters you type in. To ensure you don't miss something relevant use wildcard and truncation symbols to include spelling variations to widen your search.
A truncation symbol (*) retrieves any number of letters - useful to find different word endings based on the root of a word
africa* will find africa, african, africans, africaans
agricultur* will find agriculture, agricultural, agriculturalist
A wildcard symbol (?) replaces a single letter. It's useful for retrieving alternate spelling spellings (i.e. British vs. American English) and simple plurals
wom?n will find woman or women
behavio?r will find behaviour or behavior
Hint: Not all databases use the ? and * symbols, so check the online help screens before you start.
Watch our video on literature searching tips and tricks
Jump to 01:45 for truncation and 05:46 for wildcards.
There are three main search operators:
The individual tabs in this box explain these in more detail.
This video covers a variety of techniques for creating a comprehensive search including using 'AND' and 'OR' to build a search statement.
Using 'OR' will bring you back records containing any of the search words you have linked with 'OR'. It will return items that include both terms, but will also return items that contain only one of the terms.
This will give you a broader range of results.
OR can be used to link together synonyms. These are then placed in brackets to show that they are all the same concept.
women AND Africa
If you're getting too many results, using AND can be a good way to narrow your search.
Most databases put an implicit 'AND' between the words you type. If you are creating a search statement you should type it in to make sure your words are combined correctly.
women NOT Africa
Use this with caution - by excluding results in this way you might remove key resources from your results. Only use this technique if there is a clearly identifiable set of irrelevant results which have no link to the topic you are trying to retrieve.
Sometimes your search may contain common words (i.e. development, communication) which will retrieve too many irrelevant records, even when using an 'AND' search. On many databases, including Google, to look for a specific phrase, use quotation marks:
Your search will only bring back items containing these exact phrases.
Some databases automatically perform a phrase search if you do not use any search operators. For example, "agriculture africa" is not a phrase used in English so you may not find any items on the subject. Use AND in between your search words to avoid this.
On Scopus to search for an exact phrase use { } e.g. {agricultural development}. Using quotes on Scopus will find your words in the same field (e.g. title) but not necessarily next to one another.
For instance, if you were searching for references about women in Africa, you might retrieve irrelevant records for items about women published in Africa. Performing a proximity search will only retrieve the two words in the same sentence, making your search more accurate.
Each database has its own way of proximity searching, so it's important to check the online help before you start. Here are some examples of the variety of possible searches:
On most databases you can type in a search statement (or search string), which involves combining your search words using search operators. When creating a search statement you must use brackets to ensure correct processing of the search. The database will read your search from left to right, but will perform bracketed terms first (the same way bracketed terms are dealt with first in mathematics).
This is an example search statement bringing together our three concepts using the techniques described above. Each concept is separated by AND.
(wom?n OR gender OR girl*) AND ("agricultural development" OR farming) AND africa*
Try using the generator below to come up with your own search statement.
Many databases, including Web of Science and Scopus, save you having to create a statement by giving the option to add rows to the search screen. You can then type each concept and its alternative words into separate search boxes - just copying the layout of your search plan. The database takes care of the brackets and inserts AND between the rows.
Example from Web of Science:
If your search isn't finding very much, or you are finding it hard to frame your search successfully, there are some other techniques and tools you can try.
If you find a few relevant papers when searching on databases look to see if there is a facility to view related papers. One way of doing this is via citations and references. The Web of Science database, Summon and Google Scholar all display the number of papers which have cited each paper since it was published. Clicking on this number will take you forwards in time to other potentially useful papers. It may also be possible to view a list of papers referenced in each one.
Use to search across a number of databases covering a range of subject areas. Provides references to journal articles, books, conference papers, patents, research data and other materials.
Google Scholar is the academic version of Google. It allows you to search for scholarly literature (journal articles, books, patents) from a variety of sources, including academic publishers, professional societies, and online repositories.
There are a growing number of tools you can use to discover papers related to the ones you already have. These allow you to explore similar papers and their authors in more detail. Examples include ResearchRabbit and InCiteFul.