This blog post is the first of our Searching top tips series. These tips are especially important for systematic and comprehensive searching. This first post focuses on choosing which databases to search.
In order to undertake a comprehensive search you will need to search more than one database. There are many databases available so you should familiarise yourself with those most appropriate to your research topic. Ask a librarian if you’re unsure!
Core biomedical databases – Medline/PubMed and Embase
For biomedical topics, at the very least you should search Medline and Embase. These databases are both large biomedical databases. In most cases you will not need to search PubMed as well, as the majority of PubMed records are also within Medline. You could however consider a supplementary search of PubMed following the method recommended by Duffy et al. (2016).
Specialist databases to be searched depending on topic
This is not an exhaustive list so do speak to a librarian, especially for subjects which broach non-health and biomedical areas such as bioengineering and technology.
– CINAHL (Cumulative Index of Nursing and Allied Health Literature) via EBSCO – a good database for subjects related to nursing, allied health, public health and complimentary medicine.
– AMED (Allied and Complimentary Medicine) (Ovid) – a small database covering allied health and complimentary medicine. Also good for palliative care.
– Cochrane Central Register of Controlled Trials (CENTRAL) – Contains randomised and quasi-randomised controlled trials, so highly recommended if you are looking for this study design.
– PsycINFO (Ovid) –psychological and behavioural sciences
– Maternity and Infant Care –midwifery, pregnancy and birth, postnatal care and infant feeding, including care of the infant from 0-2 years
– ASSIA (Applied Social Sciences Index and Abstracts) – covers social and psychosocial topics, as well as literature around social services such as social work and prison services
– Social Care Online –social care and social work
– HMIC – UK focused health and social care management information. A rich source of grey literature.
– Health Business Elite – Healthcare management and administration
Multidisciplinary/citation reference searching databases
There are two multidisciplinary databases (Web of Science Core Collection and Scopus) worth considering for topics benefiting from a broad search crossing the scientific (e.g. engineering and technology), social sciences and arts and humanities.
Web of Science Core Collection and Scopus also allow you to do something called cited reference searching, which is a supplementary search technique whereby you can identify articles which have cited a known relevant article in the hope that papers referring a relevant study may also be relevant.
Grey and unpublished literature
If you are undertaking a systematic review or a comprehensive search then it’s important to search for unpublished studies and grey literature (studies not commercially published). Searching for unpublished clinical trials can help to reduce the problem of publication bias.
To identify registered clinical trials, we recommend searching the WHO International Clinical Trials Registry Platform. Grey literature can exist in many formats, such as reports from professional organisations or research groups, or even as a PhD thesis. Conference abstracts are another source of grey literature that can be searched for in some databases and may report on research that is never fully written up in an academic journal. Get in touch with one of our librarians if you’d like advice about potential sources of grey literature.
References and further reading
Duffy S, de Kock S, Misso K, Noake C, Ross J, Stirk L. (2016) Supplementary searches of PubMed to improve currency of MEDLINE and MEDLINE In-Process searches via Ovid. Journal of the Medical Library Association, 104(4):309-312. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5079494/
Higgins JPT, Green S (2011) 6.2 Sources to search. In Higgins JPT, Green S (eds.) Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration. Available at: http://handbook.cochrane.org/chapter_6/6_2_sources_to_search.htm