Internet Health 2003;1:5

Vinod Scaria

Medline is perhaps the most popularly used database by Medical professionals and students. Every Doctor or Medical student who regularly uses the Internet would have certainly stumbled on any of the MEDLINE utilities available on the Internet. A practicing doctor would find MEDLINE unavoidable for his day-to-day practice and a Medical Student would find the database immensely useful in advancing knowledge.

WHAT IS MEDLINE?

MEDLINE [MEDlars onLINE] is a bibliographic database maintained by the National library of Medicine [NLM] and covers the fields of Medicine, Dentistry, Nursing, Veterinary Medicine and Health research.

MEDLINE Indexes over 3K biomedical journals and the database is updated weekly and includes about 400,000 papers every month.  Over 85% of the journals are in English Language. Non English Language papers are indexed with an abstract in English.

MEDLINE indexes Journals from 1966 to current, and the enormous database hosts about 9 Million records.

DIFFERENT VERSIONS OF MEDLINE

Different versions of the MEDLINE Database are available. They Include CD ROM versions  and Internet versions. Apart from the NIH website PubMed, many other online versions of MEDLINE are available in different flavours.

Medscape, Healthgate, Community of Science, Kfinder, Infotrieve, WebSPIRS, OVID, , Paperchase and BioMedNet are just some of them.

PUBMED

PubMed is the NIH website that provides access to MEDLINE free of cost.

The Pubmed Website is maintained by NCBI which also maintains other databases related to Biotechnology and Genetics.

ADDITIONAL FEATURES IN PUBMED

Apart from Indexing Journal abstracts, PubMed also provides a link to the Full Text article if available Online. The Full Text version may be free as in open access Journals or may be restricted to subscribers. In addition, it also links to PubMedCentral, a free online archive of full text Biomedical journals, and the Bookshelf, another utility of NIH, which publishes entire books online.

Every indexed abstract is provided with a unique PubMed ID [PMID], an eight digit code which enables one to link directly to an abstract in PubMed.

SEARCHING PUBMED

Pubmed allows complex searching incorporating AND OR and NOT strings.

Eg: If you need to search for an article on tuberculosis and Rifampicin, you could use the string tuberculosis AND rifampicin, and if you need to see articles excluding meningitis, you could modify it as tuberculosis AND rifampicin NOT meningitis.

Pubmed insists that you always optimize your search queries using the MeSH [Medical Subject Headings] A MeSH browser is also provided in the PubMed website: http://www.ncbi.nlm.nih.gov/entrez/meshbrowser.cgi

ADVANCED SEARCH

You could also search specific areas in the Journal like authors, abstract etc. The Preview/Index utility http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=Index&DB=PubMed lets you easily configure your search.

Your search results page looks like this:

You could now sort your queries based on Publication date, journal name or Author’s name.

CUSTOMISING SEARCH RESULTS

By default, Pubmed displays only the first 20 abstracts pertaining to your query with links to subsequent pages containing the subsequent abstracts. You could significantly increase this to a maximum of 500 abstracts per page by clicking on the tab designated ‘show’ on the top and bottom banners.

SAVING SELECTED ABSTRACTS

Each displayed abstract is numbered and provided with a checking field adjacent to it. You can check the needed abstracts and save it to your hard disk or to the clipboard and then finally to your hard disk when you have checked all the required abstracts.

The selected abstracts are saved in an fcgi file, which can be opened using any browser or text formatting tools or directly loaded into a database.

BROWSING PUBMED

You could indeed browse through the Pubmed website. The Pubmed website lets you browse through the database using utilities like the Journal browser http://www.ncbi.nlm.nih.gov/entrez/jrbrowser.cgi , the

MeSH browser: http://www.ncbi.nlm.nih.gov/entrez/meshbrowser.cgi and the Citation Matchers: http://www.ncbi.nlm.nih.gov/entrez/query/static/citmatch.html and http://www.ncbi.nlm.nih.gov/entrez/getids.cgi   .

The Clinical Queries utility http://www.ncbi.nlm.nih.gov/entrez/query/static/clinical.html is an extremely useful resource for practicing doctors.

LINKING TO PUBMED ABSTRACTS

You can link to a specific abstract indexed in Pubmed. Just Construct the URL as follows:
http://www.ncbi.nlm.nih.gov/entrez/utils/elink.fcgi?dbFrom=database&db=database&from_uid=UIDs

Databases include (e.g., db=pubmed, dbFrom=nucleotide, etc):

PubMed is the default dbFrom, (e.g., dbFrom=pubmed) and all databases is the default db (e.g., db=all).

Only one dbFrom may be specified, however several db are possible. Separate dbs with a comma, e.g.,

db=protein,nucleotide
db=all

UIDs include the PubMed identifier (PMID), the molecular biology database identifier (GI), and the OMIM MIM numbers.  Separate multiple UIDs with a comma, e.g.,

from_uid=11801962,11801297,11801285

Results are combined and ranked using the average score for individual citation scores.

Include a second from_uid parameter to retrieve the relevancy scores for another set of UIDs,  e.g.,

from_uid=11802254,11802251,11802243&from_uid=11063292,11757762

OTHER MEDLINE PROVIDERS

Many other websites provide MEDLINE on the Internet in their own flavours.

Medscape, Healthgate, Community of Science, Kfinder, Infotrieve, WebSPIRS, OVID, Paperchase and BioMedNet are just some of them.

These resources are also available through many other websites, which utilize the databases of the licencees.