How to Choose a Research Question for an MD Thesis
A practical framework for turning a clinical interest into a focused, feasible and defensible thesis question.
Reference Management
How to Search PubMed Effectively
Use MeSH terms, Boolean operators, field tags and filters to find relevant papers faster.
Reference Management
A few techniques can turn a frustrating PubMed search into a focused, reproducible one.
Break your question into concepts
Use PICO to identify two to four core concepts. You rarely need to search every element — the population and intervention or exposure are often enough to start.
Combine MeSH and free-text terms
MeSH (Medical Subject Headings) are controlled vocabulary terms assigned by indexers. Use the MeSH database to find the right heading, then also add free-text synonyms in title/abstract ([tiab]) to capture recent articles not yet indexed.
Use Boolean operators correctly
- OR within a concept (synonyms) — broadens.
- AND between concepts — narrows.
- Use parentheses:
("Diabetes Mellitus, Type 2"[Mesh] OR "type 2 diabetes"[tiab]) AND (metformin[tiab])
Apply filters thoughtfully
Filters for article type, species, language and date are useful, but note which ones you apply. For systematic reviews, avoid restrictive filters without justification.
Save and document
Create a free NCBI account to save searches and set alerts. Record the exact search string, date and number of results — you will need these for your methods section.
This article is for general educational purposes. Always follow your institution’s guidelines and your guide’s advice.