The Cochrane Handbook
See Section 6.4

Searching for Studies: A Guide to Information Retrieval for Campbell Systematic Reviews
From the Campbell Collaboration (August 2010)

Useful MeSH for Evidence-Based Medicine
Tufts University, Hirsh Health Sciences Library

Scoping Studies
from the UBC Health Library Wiki

PubReminer - Detailed analysis of PubMed Search Results

MeSH on Demand - Web-based tool that suggests MeSH terms from your text such as an abstract or grant summary. Also displays the PMIDs for the top ten related citations in PubMed that were also used in computing the MeSH term recommendations.

Yale MeSH Analyzer - A MeSH analysis grid an help identify the problems in your search strategy by presenting the ways articles are indexed in the MEDLINE database in an easy-to-scan tabular format.

McMaster University Hedges Team
The focus of the Hedges Project, which is funded by the National Library of Medicine, is to investigate ways to develop and harness  search strategies ("hedges") that will improve retrieval of scientifically sound and clinically relevant study reports from large, general purpose, biomedical research bibliographic databases including MEDLINE, EMBASE, PsycINFO, and CINAHL.

PubMed Clinical Queries Research Methodology Filters Table

PubMed Search Strategies
"This blog has been created to share PubMed search strategies. Search strategies posted here are not perfect. They are posted in the hope that others will benefit from the work already put into their creation and/or will offer suggestions for improvements"

Search Filters Resource
Centre for Reviews and Dissemination, InterTASC Information Specialists' Sub-Group Search Filter Resource

Search Strategy Used to Create the Systematic Reviews Subset on PubMed

Search Filters
from the Scottish Intercollegiate Guidelines Network

Bradley SM. Examination of the Clinical Queries and Systematic Review “hedges” in EMBASE and MEDLINE.
J Canadian Health Libraries Assoc. 2010 Aug; 31(2): 27-37.

Glanville J, Bayliss S, Booth A, et al. So many filters, so little time: the development of a search filter appraisal checklist. J Med Libr Assoc. 2008 Oct; 96(4):356-361. PMID: 18974813

Jenkins M. Evaluation of methodological search filters - a review. Health Info Libr J. 2004 Sep, 21:148-163.PMID: 15318913

McKibbon A, Wilczynski N.PDQ Evidence-based Priniciples & Practice, 2nd edition. 2009

McKibbon A, Wilczynski N, Haynes RB. Retrieving randomized controlled trials from MEDLINE: a comparison of 38 published filters. Health Info Libr J. 2009 Sep, 26(3):187-202. PMID: 19712211

Sampson M, McGowan J, Cogo E, Grimshaw J, Moher D, Lefebvre C. An evidence-based practice guideline for the peer review of electronic search strategies. J Clin Epidemiol. 2009 Sep;62(9):944-52. PMID:19230612 

Sampson M, McGowan J, Lefebvre C, Moher D, Grimshaw J. PRESS: Peer Review of Electronic Search Strategies. Ottawa: Canadian Agency for Drugs and Technologies in Health; 2008.

Weiland LS, Robinson KA, Dickersin K. Understanding why evidence from randomised clinical trials may not be retrieved from Medline: comparison of indexed and non-indexed records. BMJ. 2011;344:d7501(Published 3 January 2012).  PMID: 22214757

Yoshii A, Plaut DA, McGraw KA, Anderson MJ, Wellik KE. Analysis of the reporting of search strategies in Cochrane systematic reviews. 
J Med Libr Assoc. 2009 Jan; 97(1): 21–29.PMCID: PMC260502