Worried you are going to miss that relevant article?

Its all about the words you use in your search. Consider the following when thinking of key search terms.

• Synonyms: Does everyone writing on or researching your topic use the same key words as you? Think of similar words (synonyms) and related words eg,
  you might use obese but someone else will use overweight,
  you might use teenagers but someone else might use adolescents.

• Different spellings eg, diarrhoea or diarrhea; pediatric or paediatric, tumor or tumour

• Acronyms or abbreviations eg, ECG, OCD, COPD, GDM. Even though it is sensible for authors to spell the terms in full in the article title and abstract some authors don't and use only the acronym in the article title and abstract.

• Singular or plural eg, lens or lenses, antibiotic or antibiotics.

• One word or two eg healthcare or health care

• Antonyms eg fertility infertility

• Medical terminology eg varicella or chickenpox

• Generic or brand drug names eg acetaminophen or paracetamol; ibuprofen or brufen

• Broader or narrower key search terms. Unpack the concept or key word eg if you are researching natural health products (broad term) do you need to also search using the more specific (narrower) terms that may come under the umbrella term natural health products eg dietary supplements, probiotics etc especially if you do not get enough results simply searching for natural health products.

Think about:

Truncation: (ie if a word has variant endings cut it back to a sensible stem)
Truncation allows you to search for the stem of a word with all its possible endings.
Common truncation symbols are *, $, or ?
As not all databases or web browsers use truncation check the online help within a database to find out if truncation is allowed and which symbol to use.
Note: Google Scholar and Google don't use truncation - you will need to try separate searches for comprehensive results eg cataract cognitive; cataracts cognitive.
It is best not to use truncation when first doing a search in PubMed.

Examples:
exercis* for exercise, exercises, exercising
obes* for obese, obesity
nurs* will pick up nurse, nurses, nursing (but you might get some surprising results eg, nursery, nurseries).

Phrase searching:
A phrase is a group of words functioning as a single unit. On some databases, especially Scopus, you will need to use double quotes " " to search for a phrase eg, "physical activity".
Note: It is best not to use double quotes or "phrase searching" when first doing a search in PubMed.

Punctuation
In most databases you can omit apostrophes in words.
Be careful when using the Scopus database. When searching Scopus it is best to either use truncation eg asperger*, alzheimer* or use the singular (asperger, alzheimer) as it should then automatically look for singular or plural.

Other things to consider:

• Date eg, last 5 years? last 2 years?
• English language.
• Age groups eg, neonates, young adults, over 80s.
• Study type eg, randomised controlled trials; systematic reviews; longitudinal studies; cohort studies.
• New Zealand context.