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One Health Study

Modifying search results

Tips for refining your search results

Narrow your results

If your results are too large and unfocused on your topic, look for commonalities in the irrelevant articles in your results.  Examine your search strategy for proper syntax; use subject headings; subheadings and restricting to major terms (Medline/PubMed), remove low-yield ORed terms, ANDing additional terms, searching in key fields like title, abstract or subject heading, limiting by publication type, date or language.  Use NOT operator very carefully to avoid eliminating useful results.

Broaden your results
Find additional articles by examining your search strategy for proper syntax, ORing additional terms, going to broader PubMed subject heading entries and/or removing subheadings and changing MAJR to MESH terms, looking in more databases,

If you have saved previous search strategies, use NOT to see what unique new articles your new strategy has uncovered.  Be sure to update the saved strategy to include the new terms if fruitful.

Identifying search terms

Break your research question into its main concepts. Determine synonyms for each concept and add new ones as your search evolves. Download the Yale concept table or make your own grid to keep track of terms.

Subject headings and Textwords

Look for subject headings in the indexing of useful articles, and note textwords that occur in relevant and irrelevant results.

Subject headings help to find articles on a similar topic that may use very different terminology  such as synonyms, plurals, or Britishisms.  Scroll down on this page to see an example of some of the Entry terms found by using the single subject heading word Neoplasms in PubMed, including all the variant terms such as cancer, tumor/tumour/tumours, malignancy, etc. 

The same page demonstrates that in some databases like PubMed, subject headings are hierarchical, so searching the broadest term can also search the more specific terms in the hierarchy, such as different types of neoplastic cells and neoplasms by body location.  In MeSH, one can also choose to focus on the Major subject headings, the two or three concepts that are most important in that article.  MeSH also provides subheadings that further define an aspect of the subject, such as its etiology or treatment.

Thesauri:  The page mentioned above is an example of a thesaurus, a dictionary of standardized terms used to index documents in that database that may show synonyms and definitions. 

  • In PubMed use the MeSH database
  • In other databases look for the thesaurus in the search interface.

Related article tools:  Scopus, Web of Science and Google Scholar do not have subject headings other than terms that may be imported from other sources or assigned by the author.  These may use a See Related/Find Similar, etc. feature that uses co-citation networks to identify related articles (inferring that articles that cite the same references describe similar topics).  PubMed's Similar Articles feature is based on title, abstract and subject heading terms.

Importance of textwords

Use textwords to find publications in databases that don't have subject headings, to find new concepts that don't yet have subject headings (such as new diseases, treatments or societal concepts), articles that indexers have used variant terms to index, and as a quality control measure of the thoroughness of your search strategy.   In PubMed, many newly added articles have not yet been indexed so won't be included in results using only subject headings.  To focus results, you can try searching for these terms in the title, abstract or subject heading fields.  

Indexers may vary on how they apply search terms, so a good search uses a mixture of subject headings and textwords.  

Operators

OPERATORS

Combine your search terms with operators.  Some databases require that they be capitalized (Articles+, Google Scholar)

boolean operators

AND finds items with BOTH terms, use for intersection of two ideas
OR finds items with EITHER term, use for synonymous ideas
NOT excludes items with term; use with care, useful for reviewing changed search strategy results
Other operators
phrase searching usually quotation marks, can break mapping to subject headings, usually not available with truncation
truncation usually *, sometimes ?,finds word variants that begin with the same root, breaks mapping in PubMed, not used in Scholar
wildcards used to replace one or more letters in a word
word order adjacency within a few words, words in particular order. for example term1 adj3 term2 in Ovid
processing order PubMed processes from left to right; with PubMed and most databases using parentheses can determine the order of processing. others like Scholar process by operator.  

 

Subject heading tools

Some MeSH terms to consider for the One Health Study project

Geographic locations - hierarchy of continents, regions and nations

Study types - hierarchy of different study types, including variants of epidemiologic studies

Subheadings for 

  • statistics & numerical data (includes epidemiology, ethnologymortalitysupply & distribution)
  • etiology (includes  chemically inducedcomplicationssecondarycongenital,  embryology,  geneticsimmunologymicrobiologyvirologyparasitologytransmission)
  • trends
  • prevention and control
  • diagnosis

Animals - hierarchy of animals by population group and order/species

Ecological and Environmental Phenomena - environmental, climactic and meteorological terms (note Environment includes Microbiota)