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| Các toán tử tìm kiếm Boolean× | Tìm kiếm tài liệu xám× | |
|---|---|---|
| Lĩnh vực | Kỹ năng nghiên cứu | Kỹ năng nghiên cứu |
| Họ | Process / pipeline | Process / pipeline |
| Năm ra đời≠ | 1847 (Boolean algebra); 1960s (database applications) | 1990s (formalized in systematic review guidelines) |
| Người khởi xướng≠ | George Boole and IT information retrieval practitioners | Information specialists and systematic review methodologists (Cochrane Collaboration, Health Technology Assessment) |
| Loại | Tool | Tool |
| Công trình gốc≠ | Wilkinson, M. D., Sansone, S. A., Vandervalk, B., & Rocca-Serra, P. (2011). Evaluating information retrieval systems: a guide for researchers. Expert Review of Molecular Diagnostics, 11(2), 181–190. link ↗ | Rothstein, H. R., & Hopewell, S. (2009). Grey literature. In J. P. Higgins & S. Green (Eds.), Cochrane handbook for systematic reviews of interventions (Version 5.0.2, Chapter 13). The Cochrane Collaboration. link ↗ |
| Tên gọi khác | Boolean logic, Boolean search, AND OR NOT | grey literature, gray literature, unpublished literature |
| Liên quan≠ | 2 | 3 |
| Tóm tắt≠ | Boolean search operators are logical functions—AND, OR, NOT, and parentheses—used to combine and filter search terms in bibliographic databases, library catalogs, and search engines. Named after mathematician George Boole (1815–1864), Boolean logic has been applied to information retrieval since the 1960s. These operators allow researchers to construct complex, precise searches that retrieve only articles meeting specific combinations of criteria, dramatically improving search efficiency and reducing irrelevant results. | Grey literature comprises documents and data not published through conventional commercial channels—including theses, government reports, clinical trial registries, conference abstracts, organizational policy documents, and working papers. Unlike journal articles, grey literature is not indexed in MEDLINE or Scopus and often lacks peer review. However, it is crucial for systematic reviews because it may contain null or negative findings that are less likely to be published (publication bias). Systematic grey literature searching is now a standard component of evidence synthesis and is recommended by the Cochrane Collaboration, PRISMA, and other methodological guidelines. |
| ScholarGateBộ dữ liệu ↗ |
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