If you are not getting enough articles, you probably need to broaden your search. It could also be a sign that you might not be using a database that covers your topic, so check that first. If you are in a database that you think should cover your topic, there are several techniques that you can use to broaden your search.
A technique you can use to get more articles is called pearl growing. If you retrieve even just one article that you are really interested in, click on it. In most databases you will see a list of subjects or descriptors describing your article. By clicking on any of those subjects, whichever one focuses on the the aspect you are most interested in, you will retrieve more articles with a similar focus, if they are available.
There is another way to "grow pearls." Read the titles and abstracts of articles that seem close to what you want. Do you see any terms that describe your topic that you did not use in your search? Use these new terms to do more searches.
Boolean operators describe a conceptual relationship between search terms and include: "and," "or," and "not."
Or is good to use when there are several terms that can be used to describe the same or similar concept. If you need more articles, ask yourself if there are other ways to describe your topic and include them.
Example: If you are looking for articles on the death penalty, you could enter: death penalty or capital punishment.
Using "or" indicates that either term may be present to be retrieved. An "or" search would retrieve a set that looks like the entire image-- the yellow circle, the blue circle and the green portion in between would all be retrieved. "Or" should be chosen when using several terms to describe the same or a similar concept, which will broaden the search.
When you want more articles try to think of alternate ways of describing your topic. Be flexible with your search terms when looking for resources. Some topics may have synonyms or terms that are close in meaning. For instance, when researching the Death Penalty, using the term Capital Punishment will also retrieve articles or open access sourceson the same topic.
There are also frequently terms which are not synonymous, but which indicate a built in bias about the topic. These terms can also be used to retrieve more resources. For instance, when researching abortion, the following terms can also retrieve articles or Internet sites on abortion: Pro Choice, Pro Life, Reproductive Freedom, Right to Life.
You may not always know these related and alternate terms until you start looking for resources, but you should keep an eye out as you review articles.
Some (but not all) databases have expanders that you can use to broaden your search, such as search for related words or terms, and search within the full text of the article.