The best first step is to break the topic you're searching into individual concepts. For example, if you're interested in research into the impact of urban farming on poverty, you may break it into just two concepts:
You know that you're interested in articles that include information on both of these concepts. You're not really interested in articles that talk about poverty outside the context of urban farming, and vice versa. So, when you search a database, you want to be sure that you're including all of the concepts. Your search might look like this:
urban farming AND poverty
The Boolean operator "AND" commands the database to return only records that include all of your terms.
For each of these concepts, there is more than one word that would bring up relevant articles. For example, articles on urban farming might be found by searching urban farms or urban agriculture -- likewise with poverty. There may be related terms that will return some good results.
You might want to search all of these words to bring back as many relevant articles as you can. You could broaden your search like this:
"urban farming" OR "urban farms" OR "urban agriculture" ...
poverty OR "food insecurity" OR "low income" OR poor...
To put these together, we can add parentheses () around each concept.
("urban farming" OR "urban farms" OR "urban agriculture") AND (poverty OR "food insecurity" OR "low income" OR poor)
You can use these techniques when searching most databases, including Google. Or you can use the fields provided by databases to structure your search like below:
When you do a search like poverty AND "urban agriculture" in a database, you are looking for those terms anywhere in the record. Articles will be returned that have the term in their title or abstract, as well as in other fields, such as the title of the journal or the list of subjects. This is keyword searching. You can see the results of our keyword search in a general, multidisciplinary database below:
There are special terms called subject headings (or sometimes subject terms) that databases use so that there will be a consistent term to describe a single concept. For example, we know that the terms "urban farming" and "urban agriculture" can be used to describe the same concept. A database may include a specific subject heading for "Urban Agriculture" that will be assigned to any articles on that topic no matter what term the authors used.
It's a good idea to try searching with subject headings when:
Also, keep in mind that focused subject databases will include the most specific subject headings. In the screen capture above, the general, multidisciplinary database does not have a subject heading for our concept urban agriculture. However, the database GreenFILE, which is focused on environmental and sustainability topics, does: