How to Search in PubMed: MeSH Terms
The first thing you need to do when collecting terms is to search for the correct keywords. Most literature databases use controlled terms, also called keywords, but the way in which they are used may vary.
PubMed uses Medical Subject Headings ( MeSH terms ). These controlled vocabulary thesaurus terms are used for indexing articles for PubMed. These terms assigned to an article, provide information about the article’s content. In PubMed, the assigned terms all belong to a setlist of keywords: the MeSH Database.
Watch the an example of a detailed MeSH Search below:
More About MeSH
1. Definition
Make sure you always double check the description to see whether the term is relevant to your topic.
Anti-Bacterial Agents
Substances that reduce the growth or reproduction of BACTERIA.
Year introduced: 2004(1963)
2. Treeview
Keywords are sorted in the MeSH database according to a treeview, showing the position of the term in a hierarchy. It can be useful to examine terms located higher in the tree to see what they cover. You might find that these terms are more appropriate to your query. On the other hand, you might also benefit from terms located lower in the tree to help you find articles that are far more specific.
3. Explosion
The standard setting in PubMed is to search for a term including all narrower terms below it in the hierarchy. You may opt to omit these narrower terms from your search by ticking the box:
Do not include MeSH terms found below this term in the MeSH hierarchy
PubMed (English): MeSH
MeSH (Medical Subject Headings) are standardized keywords that you can look up in the MeSH Database. The majority of articles in PubMed (over 90%) have been assigned MeSH terms to provide information on the content of the articles. MeSH terms are manually assigned by indexers of the NLM (National Library of Medicine).
Why do I need to search with MeSH?
By using MeSH terms in your search, the various synonyms of a term are automatically included in the search query.
Example: In literature the concept of ‘cancer’ can be described in various ways: cancer, cancers, tumor, tumour, neoplasms etc. If you were to search using the word ‘neoplasms’ only, you would miss articles. If you search with the MeSH term ‘neoplasms’, you will find articles on this subject no matter which words were used to describe this concept.
Demo: How to search with MeSH (2:22)
Watch this video from Laupus Health Sciences Library (East Carolina University) for a demo on the MeSH database.
To search PubMed using the selected MeSH terms, click on ‘Search PubMed’ after selecting the MeSH terms in the MeSH database (with ‘Add to Search Builder’).
Searching with MeSH alone is not enough, why not?
- You will not find the latest articles
MeSH terms are manually assigned to articles. As this takes time, the latest articles will not have been assigned any MeSH terms yet and therefore will not appear in your search results if you only use MeSH terms in your search. - There is no appropriate MeSH term
Sometimes there is no MeSH term for the concept you are interested in. In that case, it is important to search (additionally) for relevant words in the title and abstract, for instance.
MeSH — extra information
The MeSH Database provides additional information on all MeSH terms (see the Raw Foods example below):
- Definition of a MeSH term
- Entry terms: similar words (synonyms) that are grouped together under the same MeSH term
- The ordering of related MeSH terms; MeSH terms are hierarchically ordered in an inverted tree structure. A MeSH term can belong to multiple categories.
- Closely related terms (if present) under See Also
There are several ways to search more specifically with a MeSH term
(see the Intensive Care Unit example below):
- Subheadings are aspects or contexts to restrict a MeSH term.
For instance, if you are looking for articles about the supply of resources in ICUs, you can tick the subheading supply and distribution and search with "Intensive Care Units/supply and distribution"[MeSH]. - With Major Topic you will only find articles where the MeSH is the main topic.
For example, searching with "Intensive Care Units"[Majr] you will not find articles where this topic is covered to a lesser extent. - No Explode
When searching with a MeSH term such as "Intensive Care Units"[MeSH], by default you will also search with the more specific MeSH terms that are located under this term in the tree structure: Burn Units etc.
If you do not want to include these more specific terms, you can turn this off by checking 'Do not include . '. You will then be searching with
"Intensive Care Units"[MeSH:NoExp], where NoExp means no explode.
Tip: compare the number of results of the four searches mentioned above.
Pharmacological Action
In the MeSH database you can also find Pharmacological Action terms. This is a special type of MeSH that allows you to search for pharmacological action, e.g. "Serotonin Uptake Inhibitors"[Pharmacological Action]. On the information page you can see which drugs are included.
If you would only search with "Serotonin Uptake Inhibitors"[MeSH], then you would miss articles about Prozac for instance ("Fluoxetine"[MeSH]).
How to use PubMed
MeSH is a pool of medical terminology with very specific definitions for each word.
They are used to tag articles with the relevant content in databases like PubMed, Cochrance. Using the Medical Subject Headings. (MeSH) is efficient because they search for matching content rather than text .
Where can you find MeSH tags?
For any particular article, the related MeSH terms can be found at the bottom of the Article record page.
Searching with MeSH terms
Searching with MeSH terms retrieves articles with content specific to the MeSH term searched.
Choosing your specificity.
MeSH terms have a "hierarchy". The more specific the term is, the lower it is on the MeSH term tree, the less articles there are with such specific content. Conversely, umbrella terms such as "Diabetes mellitus", which defines disorders characterised by high blood sugar and glucose intolerance will retrieve more articles less specific to any one disorder. This hierarchy shows the relationships between terms and get lead you in finding terms that you might not be aware of
Below is an example of a MeSH term tree
To search with MeSH terms, one needs to retrieve the MeSH terms describing exactly what you're interested in from the MeSH database and add it into a Search Builder.. Please note that you can only retrieve MeSH terms in your results and not related articles. Select your desired MeSH terms and add them into the Search Builder to search in PubMed.
A Search Builder helps you to narrow or expand your search by combining multiple MeSH terms with Boolean operators (AND, OR and NOT) and retrieve results with the relevant content.
As always, you must also be “flexible” to not use MeSH if you yield too little results.
Step 1: At the MeSH database page, key your subject matter into the search bar and select the most relevant MesH term from the database.
Step 2: After clicking the search result, a page detailing the definition of the MeSH term will load.
Select the MeSH subheadings that you're interested in, then click "Add to search builder" at the top right corner of the page.
Step 3: After clicking the subheadings you want, you can narrow your search or widen your search. Only the related subheadings to the MeSH terms will appear.
- To expand your search results (include articles with any of the subheaders for the major heading that you have chosen), check multiple subheadings and clicked "Add to search builder". PubMed will process it with the "OR" Boolean operator
- To narrow your search results ( only include articles with all the subheadings that you have chosen), check one subheading then add it to the search builder, and repeat with another subheading. PubMed ;will process it with the "AND" Boolean operator.
When you have constructed your desired search, click "Search PubMed" below the Search Builder.
To reuse your search terms, copy the current Search Details (found at the bottom of the right most column of the page, as shown below). and paste your copied Search Details into the Search Builder before clicking "Add to Search Builder" and clicking "Search Pubmed". This will allow you to include your search results. If you want to expand your search, make sure the terms are connected via the "OR" Boolean operator.
3.8. Поиск по предметным рубрикам (MeSh Sеаrch)
Поиск по предметным рубрикам (МеSH) может вестись с использованием МеSH браузера или с помощью Limits.
3.8.1. MeSh браузер (МеSh Вrоwser)
Браузер дает возможность «рыться» в словаре предметных рубрик (тезаурусе). С его помощью можно выбрать наиболее точный термин, выражающий содержание поискового запроса.
МеSH браузер позволяет:
видеть МеSH термины в иерархической (от общего к частному) структуре;
выбирать нужные МеSH термины для поиска;
ограничивать поиск только основными (mаjоr) МеSH терминами, представленными в статье;
выбирать нужные подрубрики (subhеаdings);
выбирать нужные термины в иерархической последовательности, если введена перекрестная ссылка;
Чтобы начать поиск в МеSH, кликните на надписи МеSH Browser на левом поле гланого экрана (sidebar). Таким образом вы откроете поисковый экран МеSH. Напечатайте нужный вам термин в поисковом окошке, например, arthritis (артрит) и кликните на Gо или нажмите Еntеr. Откроется следующее окно, где вы увидите определение термина и будет показана его иерархическая структура (MeSH tree), т.е. список родственных терминов. Нужная вам рубрика будет выделена жирным шрифтом.
Если введенный вами термин не является разрешенной предметной рубрикой, то вы увидите объяснение, какой именно термин вам нужно использовать, или же вы сможете выбрать наиболее подходящий термин из предлагаемого списка.
К
ликнув наDеtailеd Displаy (показать подробно), вы откроете перечень подрубрик (Subheadings), которые относятся к данному поисковому термину. Подрубрики выражают различные аспекты рассмотрения интересующего вас термина, например, артрит лечение; артрит диагноз; артрит эпидемиология, и т.д. Вы можете выбрать одну, несколько или все подрубрики, относящиеся к
Каждая рубрика имеет свои собственные подрубрики.
Все подрубрики будут включены в ваш поиск автоматически, если только вы не выбрали одну или несколько из них, кликнув в соответствующих окошках.
Внизу перечня подрубрик указаны две команды, позволяющие сделать ваш поиск еше более точным:
Restrict Search to Major Topic headings only (ограничить поиск только главными рубриками) позволяет отобрать только те статьи, в которых данный предмет является главной темой;
Do Not Explode this term (не расширять этот термин) исключает из поиска статьи, которые содержат подчиненные термины, в нашем примере различные виды артрита. Если включить эту команду, PubMed найдет статьи об артрите в целом, но не о подагре.
Кликнув на Аdd (добавить), вы включите данный термин в ваш поисковый запрос. Таким же образом вы можете добавить еще один или несколько терминов к вашему поиску. Кликнув на стрелочку возле АND, вы также можете изменить логические операторы между терминами. Для того, чтобы получить результат поиска, кликните на РubМеd Sеаrсh. После этого вы будете возвращены к главному поисковому экрану, где вы увидите количество полученных документов по вашему запросу. Если число документов слишком велико, рассмотрите другие возможности ограничить ваш результат, например, введите временные рамки с помощью Limits.