Tag: Boolean logic

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PubMedissa on nyt yli 25 miljoonaa viitettä – Miten löydät niiden joukosta ne joita tarvitset? / PubMed now has more than 25 million citations – How to find among them the ones you need?

PubMed-tietokantaan tallennettiin 16.6.2015 kahdeskymmenesviidesmiljoonas viite. Haku yhdellä tai kahdella hakusanalla tuottaa valtavasta tietokannasta niin suuren määrän viitteitä, että täsmälliseen tiedontarpeeseen sopivan löytäminen vie paljon aikaa. Miten hakutulosta saisi toisaalta osuvammaksi mutta myös kattavammaksi?

Näillä keinoilla

  • Haun suunnittelu
    • Aihetta kuvaavat käsitteet ja niitä vastaavat hakusanat
  • Boolen logiikka
    • Videossa ei haeta PubMedistä, mutta sama logiikka toimii kaikissa tietokannoissa
    • Hakulauseella “pulmonary tuberculosis” AND (treatment OR therapy) saa täsmällisemmän tuloksen kuin haulla tuberculosis treatment
  • MeSH-termit
    • Videossa haetaan influenssarokotteiden mahdollisia haittavaikutuksia kananmuna-allergikoille
    • edellisestä aiheesta hakulause MeSH-termein voisi olla “Tuberculosis, Pulmonary/therapy”[Mesh]
  • Rajaukset
    • PubMedin vasemman reunan rajausmahdollisuuksista osa on piilossa (klikkaa more) ja muutenkin rajausten tekeminen on monivaiheista
    • Kannattaa silti käyttää tilanteen mukaan esimerkiksi julkaisutyyppi-, julkaisuaika-, julkaisukieli- ja ikäryhmärajauksia
    • Video
    • Vältä rajausta Free full text. Se jättää hakutuloksesta pois kirjaston hankkimat ja maksamat lehdet.

 

On June 16, 2015, the 25 millionth journal citation was added to PubMed. Searching with one or two words retrieves such a huge amount of citations that it takes a long time to find the ones that answer your question. How to make the search result more accurate but also more comprehensive?

With these tools

  • Planning the search
    • The concepts that describe the topic and the terms for them
  • Boolean logic
    • Same logic of combing search terms in all databases
    • Using “pulmonary tuberculosis” AND (treatment OR therapy) gives a more accurate set of results than tuberculosis treatment
  • MeSH terms
    • Video shows how to search if there are concerns with flu vaccines and egg allergy
    • About the topic above the search using MeSH could be “Tuberculosis, Pulmonary/therapy”[Mesh]
  • Limits
    • Some of the Limit options in PubMed are hidden (click more to see them) and using the limits is sometimes complicated
    • Try anyway, depending on your topic, for example article types, publication dates, languages, and ages
    • Video
    • Avoid using the limit Free full text. It omits the journals the library has subscribed and paid for.

 

Tuulevi Ovaska
palvelupäällikkö, tietoasiantuntija
head of services, information specialist

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Frequently asked questions 3 – Combining search terms

Questions:

  • What is the meaning of AND, OR and NOT in searching?
  • What is Boolean logic?
  • How do I use my search terms in a database?

Boolean logic organizes concepts together in sets. When searching databases or online catalogs, these sets are controlled using Boolean operators OR, AND and NOT.

Use OR to combine synonyms, close terms and alternatives.

For example:

  • newborn OR neonate
  • sepsis OR “blood poisoning”
  • running OR jogging

Though it seems very simple, it is sometimes confusing, as Boolean OR is actually AND-OR, meaning either-or or both.

OR

Use AND to limit the search to only those results that have all the terms combined with AND.

For example:

  • newborn AND diabetes
  • running AND “knee injuries”
  • sepsis AND “intensive care”

and

If you need both OR and AND, use brackets to combine the sets logically.

For example:

  • (newborn OR neonate) AND diabetes

Use NOT to exclude terms.

For example:

  • newborn NOT premature
  • running NOT sprint
  • sepsis NOT severe

not

Watch a short video!

Boolean logic is named after the nineteenth-century mathematician George Boole.

 

By: Tuulevi Ovaska, Head of Services, Kuopio University Hospital Medical Library, University of Eastern Finland Library