===== 🔍 Systematic Search =====

==== 📌 Definition ====
A **systematic search** is a structured, transparent, and reproducible method for identifying all relevant literature on a specific research question. It is a fundamental step in **systematic reviews** and **meta-analyses**, designed to **minimize selection bias** and ensure comprehensive evidence retrieval.

==== 🧱 Key Characteristics ====
  * Based on a clearly defined **research question** (often using PICO: Population, Intervention, Comparison, Outcome)
  * Uses **multiple databases** (e.g., PubMed, Scopus, Cochrane, Embase)
  * Includes **predefined search terms** and **Boolean operators** (AND, OR, NOT)
  * Applies **inclusion and exclusion criteria** consistently
  * Documents the entire process (databases used, search strings, dates, filters applied)
  * May include **grey literature**, conference abstracts, or clinical trial registries

==== 🔬 Example (from neuroscience study) ====
> A systematic search was conducted in PubMed, Scopus, Web of Science, and Cochrane databases using terms related to “NSAIDs,” “craniotomy,” and “postoperative bleeding.” Studies comparing NSAIDs to non-NSAID analgesics in neurosurgery were selected based on predefined eligibility criteria.

==== 📌 Purpose ====
  * Maximize **completeness** of evidence retrieval
  * Reduce **bias** in the selection of studies
  * Ensure **reproducibility** and **transparency** of the review process

==== 📂 Output ====
  * A **PRISMA flow diagram** showing study selection
  * A list of all included and excluded studies with justification
  * Search strategy appendix (often required in publications)