When searching in a database you can get more relevant results by defining what you are looking for and using keywords wisely. Here are some useful tips.
Finding search terms
When searching for information, the search terms you use make all the difference. They need to be broad enough to cover your research question, yet specific enough to reduce irrelevant hits. Finding information is a process, and we have listed a few tips and tools to help you find the terms to use.
Use both free text and controlled vocabulary
By combining your standard search terms with the ones provided in a database thesaurus, you will have a better chance of finding relevant information.
- Free text searches are typically run in title, abstract, and keywords fields.
- Many databases provide a thesaurus (a hierarchial list with controlled subject terms), and they are a great tool not only for searching from, but also to browse and thereby finding search terms in a hierarchical context. But never trust that the thesaurus' terms have been used consistently in the database! For a systematic search, you should always combine with free text synonyms.
- A biological taxonomy is a special kind of hierarchical thesaurus, available in e.g. Biosis and CAB abstracts.
Keep in mind that the same phenomenon can have different names in different subject areas.
Consider the hierarchy of your terms
A simple term might capture what you need, and there is no need to add extensions for that term unless you are looking for the extended term only, e.g. pig* covers both pig, pigs, pigeon, "domestic pig*" and "pig* in space" and any other words and phrases beginning with or containing pig.
Start with a few key articles and select relevant terms from the title, abstract, and keywords. Run a test search with these terms. If this captures other highly relevant articles, try to find more terms in them. Repeat as needed.
Tools for finding terms
Here are some tools that can be useful for translating terms e.g. from Swedish to English:
Combining search terms
Combine terms with the Boolean operators AND, OR, NOT.
- OR: Searches all terms, use for synonyms. One or all can be included.
- AND: Combines terms. All must be included.
- NOT: Excludes terms. Note that this may also exclude relevant information!
When a combination of search terms turns out to be too broad and a specific phrase search is too narrow, proximity operators may come in handy to find articles where terms occur close to each other. The syntax for proximity searching differs between databases, so make sure to check the help files.
Web of Science
Use NEAR/x to find records where the terms are within a specified number of words of each other.
"agricultur* NEAR/5 challenge*" retrieves articles where the two words are found within 5 words from each other, regardless of the order of appearance.
NEAR without specified number searches within 15 words, which is approximately within a sentence.
You can choose between two Proximity operators:
- W/n indicates distance between words, but not the order, e.g. "journal W/2 publishing", where journal can be found within a distance of two words from publishing.
- PRE/n can be used when terms must appear in a specific order, e.g. "behavioral PRE/3 disturbances", where behavioral precedes disturbances within three words. Example: "behavioral sleep disturbances", "behavioral disturbances".
By using truncation (shortening) you can search for various forms of a word. The symbol used for truncation varies in different databases, but it is often an asterisk (*) or sometimes a question mark (?).
"farm*" retrieves anything beginning with "farm", e.g. "farmer", "farmers", "farming".
Phrase searching can be used when searching for search terms consisting of more than one word, such as the name of an organization, an author, a long title, or a specific combination of terms. The search will only retrieve records with the words in exactly the specified order. Many search tools use quotation marks to denote a phrase, other tools offer a phrase search alternative directly in the menu.
"food safety" will find records with the terms in that exact order and spelling, but not records where the terms appears separately.
If you have more than one Boolean operator (AND, OR, NOT) in your search string, make sure to group the terms with parentheses or place them in different search boxes.
In most databases, parentheses can be used to group terms and to express in what order the database should search the different terms and expressions. The parentheses tells the search engine to search the terms within them first, together, and then combine them with the terms outside of the parentheses.
Always use this possibility to control how your search terms relate to each other. An alternative is to write the different groups of terms in different search boxes.
- "(horse OR pony) AND riding" will capture results about both horse riding and pony riding in all databases.
- "horse OR pony AND riding" would be interpreted differently in different databases depending on how they prioritize the operators AND and OR. It is most likely you will get hits with "pony AND riding", or everything about "horse", regardless if they appear in the same article or not.
Search in blocks
Search for one terms group or aspect at the time, using OR, to make sure that all aspects/search blocks retrieve combinable hits. This allows you to adjust your search string if needed. The search history feature can be useful here as it provides an overview and the possibility to combine search sets in an effective way.
Search one aspect at the time:
- (biodiversity OR diversity OR diverseness OR variety)
- ("urban area*" OR cities OR city OR town*)
- (park* OR "green area*" OR green space*)
Then combine the search blocks, using AND, either by entering all search terms within parentheses (Alt 1), or by by using the search sets number (Alt 2):
- Alternative 1: (biodiversity OR diversity OR diverseness OR variety) AND ("urban area*" OR cities OR city OR town*) AND (park* OR "green area*" OR green space*)
- Alternative 2: #1 AND #2 AND #3
Alerts – a way to save time
Many databases allows you to save your searches as alerts. Then you will get messages with updated results directly without having to check the database.
Note: You have to register an account and log in to the database to be able to save your searches.