Ensure you have a clear idea of what you're looking for, to avoid wasting time by searching vaguely.
Use PICOT to define concepts: Population; Intervention; Comparator; Outcome; Time frame.
Start with the 2 or 3 most essential PICOT terms, and add others in if you need to, e.g. if the search results are not specific enough.
So you won't miss relevant information if the authors have used different terminology.
How do we find synonyms? Brainstorm and gather synonyms from any sources, such as Wikipedia, or journal articles found through searching the databases or Google Scholar.
When do we add wildcards? Use the truncation wildcard, (the asterisk symbol *) to pick up alternative word endings by placing the asterisk at the end of the root of the word, e.g. child* for child, children
When do we add quotes? If we need the database to return results where the terms appear next to each other and in the same order, e.g. 'iliotibial band syndrome'.
Example searches:
(fish oil* OR "omega 3") AND (eczema OR "atopic dermatitis")
("deep vein thrombosis" OR DVT) AND diagnos* AND d-dimer
Remember to look for the most synthesised information available. As a general guide, we would seek information from these sources in order: information from a point-of-care tool, a clinical guideline, a synopsis, a systematic review, an individual study.
To use individual studies as evidence, identify the most appropriate study design for the type of question (intervention, diagnosis, etc.).
Appraise systematic reviews and studies for quality.
The basic steps for in-depth searching are the same as for rapid searching, however extra time and effort are put into certain steps, including gathering synonyms, adding subject headings (MeSH for Medline) and translating the search for more databases.
Write a question representing what you want to find about about at this point of your work (you'll probably have different questions at different stages of your work – use these steps each time). PICOT can be used if your question fits that model, otherwise try to pull out the main concepts.
Example topic:
The effect of testosterone on bladder function.
Pull the key concepts out of your question / topic of interest.
Example topic:
The effect of testosterone on bladder function.
Key search terms:
1: bladder 2: testosterone 3: maybe effects?
For in-depth searching you will put more time and effort into identifying synonyms, as you are searching more thoroughly for papers that may be harder to find. Ways to find synonyms:
As you build your list of synonyms, add the * wildcard, and quotes " " for phrases where appropriate to your search words.
Example topic:
The effect of testosterone on bladder function.
Key search terms with synonyms, wildcards and quotes:
bladder – urothelium
testosterone - no other words for this concept?
effects – bladder contractility, mediator release, acetylcholine, ACh, adenosine triphosphate, ATP, prostaglandins, overactive bladder syndrome, OAB
For each of your search words, you should see if there's a standardised subject heading you can also include in your search (this is an essential part of systematic literature reviews, and best practice for thorough literature searching).
Here's how to do it in PubMed:
Other databases have similar subject heading systems which work in a similar fashion, e.g. Ovid Medline also uses MeSH, Embase uses the Emtree system, CINAHL uses CINAHL headings etc. It is always a good idea to at least include MeSH terms for your PubMed or Ovid Medline search. Including subject headings in other databases is recommended if you are doing more systematic searching. If you need assistance finding subject headings please contact the HSM Faculty Librarian.
Example topic:
The effect of testosterone on bladder function.
With MeSH terms added:
bladder OR "Urinary Bladder"[Mesh] OR urothelium OR "Urothelium"[Mesh]
testosterone OR "Testosterone"[Mesh]effects OR bladder contractility OR mediator release OR acetylcholine OR "Acetylcholine"[Mesh] OR ACh OR adenosine triphosphate OR ATP OR "Adenosine Triphosphate"[Mesh] OR prostaglandins OR "Prostaglandins"[Mesh] OR overactive bladder syndrome OR OAB
Once you've added ANDs ORs and brackets as below, you can now copy and paste your search into PubMed and start searching.
Example question:
Is a ketogenic diet effective for reducing the frequency of seizures in children with epilepsy?
Combined with ANDs, ORs:
(bladder OR "Urinary Bladder"[Mesh] OR urothelium OR "Urothelium"[Mesh])
AND
(testosterone OR "Testosterone"[Mesh])
AND
(effects OR bladder contractility OR mediator release OR acetylcholine OR "Acetylcholine"[Mesh] OR ACh OR adenosine triphosphate OR ATP OR "Adenosine Triphosphate"[Mesh] OR prostaglandins OR "Prostaglandins"[Mesh] OR overactive bladder syndrome OR OAB)
You should keep modifying and improving your search as you go. As you search you'll notice good search words you hadn't thought of, and you can remove words that don't seem to help. You need to feel confident that you are finding all papers relevant for your current purpose.
Find the Library Guide which is most relevant to your topic. On the Journal Articles page it will list the best databases to use.
For medicine a good starting list is either PubMed or Medline (Ovid) (you only need to search one of these, not both), and Embase.