• Break down your PICO into main concepts:
  1. Population (P)
  2. Intervention (I)
  3. Comparator (C) — optional
  4. Outcome (O) — optional

• For each concept, list keywords, synonyms, acronyms, and relevant subject headings (e.g., MeSH in PubMed).

• Use OR to combine synonyms within each concept.
• Use AND to combine different concepts.
• Use NOT carefully to exclude irrelevant terms.

• Use truncation symbols (e.g., * or $) to capture word variants.
• Use wildcards for spelling variations.

• Modify syntax for each database (e.g., PubMed, Embase, Cochrane).
• Use controlled vocabulary terms where available (e.g., MeSH, Emtree).

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Research question: _“Effectiveness of aspirin for preventing stroke in diabetic patients”_