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General Search Information
- To ensure comprehensiveness, searches should be carried out in several databases, including but not limited to Medline or PubMed.
- The initial search should be translated for each additional database (for example, subject headings shoud be changed to the controlled vocabulary of the new database).
- Searches should seek high sensitivity, which may result in relatively low precision.
- Too many different search concepts should be avoided, but a wide variety of search terms should be combined with OR within each concept.
- Both free-text(keywords) and subject headings should be used (for example in PubMed/ Medline use Medical Subject Headings (MeSH)).
- Highly sensitive search strategies (filters) can be used to identify types of studies, for example, Randomized controlled trials (see the Filters tab for more information).
- Truly comprehensive searches will include grey literature searching (see box at right), and hand searching of reference lists and/or important journals.
Adapted from Part 2, Chapter 6 of the Cochrane Handbook.
Google Scholar should not be included as a database, but it can be a good source of additional information.
- Search Google Scholar after you have done your database searches.
- Look through the first 100 results.
- Choose only relevant (include) or potentially relevant (can't tell from abstract) sources that you have not already found in the database searches.
- More tips on formatting a search for Google Scholar are available at the link below:
Yale MeSH Analyzer
The Yale MeSH Analyzer can help identify the reason why some known relevant articles are missing in the initial search result set and/or identify additional search terms. You input PMID numbers of up to 20 known articles and the Analyzer will export MeSH headings and author keywords for each article in grid format.
The first link below is to a tutorial on how to use the Analyzer.
The second link is to the Analyzer itself.
Grey Literature (General)
System to search for European Grey Literature
OAIster is a union catalog of millions of records representing open access resources from collections worldwide.
Grey Literature (Dissertations/Theses & Trial Registries)
Dissertations & Theses This link opens in a new window
ProQuest Dissertations & Theses includes the full text of most U. S. dissertations and master's theses from 1995 forward as well as citations from earlier materials.
European theses and dissertations.
EBSCO Open Dissertations
A database of electronic theses and dissertations.
Doctoral theses awarded by United Kingdom higher education institutions.
NDLTD: Global ETD Search
Networked Digital Library of Theses and Dissertations
OATD - Open Access Theses and Dissertations
Aims to be the best possible resource for finding open access graduate theses and dissertations published around the world.
Metadata (information about the theses) comes from over 1000 colleges, universities, and research institutions. OATD currently indexes 2,362,547 theses and dissertations.
Canadian theses and dissertations
Australian theses and dissertations.
A service of the U.S. National Institutes of Health, ClinicalTrials.gov is a registry and results database of publicly and privately supported clinical studies of human participants conducted around the world.
WHO- International Clinical Trials Registry Platform (ICTRP)
Aims to provide a single point of access to information about ongoing and completed clinical trials. It provides a searchable database containing the trial registration data sets made available by data providers around the world meeting criteria for content and quality control.
HSRProj (Health Services Research Projects in Progress)
Information about ongoing health services research and public health projects
EU (European Union) Clinical Trials Register
Allows you to search for information on clinical trials in European Union (EU) member states and the European Economic Area (EEA) and clinical trials which are conducted outside the EU/EEA if they form part of a paediatric investigation plan (PIP).
Controlled Trials Registry
Maintained by BioMed Central, allows users to search, register and share information about randomised controlled trials.
Health Sciences Librarian