In the previous tutorial, I introduced a number of basic concepts in building search strategies in databases, and I used PubMed as the example database. However, there are some search concepts that cannot be demonstrated using PubMed, because it doesn't support them. And in this tutorial, we're going to look at another database, OvidSP MEDLINE to further explore the techniques in building search strategies. OvidSP is a search platform for many databases including MEDLINE, which is also the primary component of PubMed. PubMed, of course, has the advantages of a "Google-like" search experience, thanks to its automatic term mapping layer, excellent system response speed, and the fact that it is totally free. However, some users find OvidSP more structured and flexible. If you want to learn about the structured search process using OvidSP's search interface, you can watch my OvidSP Essential Training video series. In this tutorial, I'm going to be mainly showing you how to build search strategies in OvidSP MEDLINE with its unique command line queries, and especially demonstrate the search features that are not available in PubMed. Again, whenever you perform a complicated database search it is always handy to know where the help document is for the database. In OvidSP, the help document is right here. Your medical librarian is always a good help if none of these make sense to you at all. Let's first go over the search concepts introduced in the previous tutorial on PubMed, and see how to do the same things in OvidSP. First of all, "Field Qualifications". In OvidSP, we use what's called a "Dot-dot syntax" to indicate field qualifications. For example, if I want to search for all articles written by the author Smith J J, I can say "smith jj dot au dot". The part between the two dots is the abbreviated field name. You can put multiple field names between the dots and separate them by commas. So if I want to search for the term "hypertension" in the title and abstract fields, I can say "hypertension dot ti comma ab dot" This is very useful if you have a specific list of fields you want to search for a particular query term. Now, how do you know the abbreviations of field names? Well, you can go to "Search Fields" and under "All Fields", and here they are. So if I want to see how many articles written by Yale authors have the keyword "hypertension" in the title and abstract fields, I can say "hypertension dot ti comma ab dot and yale dot in dot". We're going to talk about this Boolean operator later in this video. Of course, you can also use this interface to construct field searches, but, as you can see, once you become familiar with this command line query syntax, it is a lot faster. Just as learning a new language, it is a matter of practice - the more searches you do, the faster you will be. Just as in PubMed, Medical Subject Headings, "MeSH", is also the controlled vocabulary system in OvidSP MEDLINE. To run a MeSH headings search, simply type in the heading followed by a forward slash. So, if I want to find all articles that were assigned the heading "hypertension", I can say "Hypertension slash". Notice that even though it is not absolutely required, it is a good practice to capitalize the first letter of each word in a subject heading for easier recognition of them as subject headings when you read the search strategies later on. Now recall that MeSH headings are assigned at the most specific level possible. So we only got this many because we did not specifically tell the system to "Explode" our term, that is, to include all articles that are assigned more specific terms under "hypertension", such as "renal hypertension". To explode the term, simply add "exp" in front of the query. So this will become "exp Hypertension slash". Also recall that each article is assigned a number of "Major Headings" which represent the primary topics of the article. To retrieve only the articles that have "hypertension" or one of its lower terms as major topic, simply add an asterisk immediately in front of the heading. So "exp asterisk Hypertension slash". Also recall that a "Subheading" represents a specific aspect of a MeSH heading. For example, the "drug therapy" aspect of the concept "hypertension". To indicate a subheading, just add the two letter subheading code after the slash. So if I say "exp asterisk hypertension slash dt". This'll give me only those articles with the subheading "drug therapy". Of course, as I demonstrated in my OvidSP essential training videos, you can achieve all of this using the provided interface here, which will also do the free text keyword to subject heading mapping for you. So I can say "High Blood Pressure" and, sure enough, it's mapped to hypertension. Exploding is automatic here. You can also limit your search to major by checking the "Focus" box here, even though it is not recommended in the initial search, as this may omit a lot of potentially relevant articles The next step is "Subheadings"... "Drug Therapy"... "Continue"... ...and you can see that this is exactly the same search as what we did in the previous command line query. Again, if you are familiar with the command line query syntax, and directly type in the query, it'll be a lot faster than clicking through multiple screens and waiting for every single page to load. There are a couple ways you can do a free text/natural language searching with OvidSP MEDLINE. The "TW" or "Text Word Search" only includes "title" and "abstract fields". So in here, I can do a text word search on "myocardial infarction" by typing "myocardial infarction dot tw dot". And I got this many results. In addition to the "TW" search, OvidSP also has an "MP" or multiple places search, so if I say "myocardial infarction dot mp dot", you can see that I got a much bigger number this time. Just as PubMed, OvidSP supports truncation, but here you can use either a dollar sign or an asterisk to indicate that. So "flavor dollar sign" or "flavor asterisk" will return records that have flavor, flavors, flavorful, flavored, et cetera. What's more, in OvidSP, you can also indicate how many letters you're truncating. So if I say "flavor dollar sign two" or "flavor asterisk two", it'll return records that contain flavored, but not flavorful. Unlike PubMed, OvidSP supports wildcard searching, where a pound sign represents exactly one character, and a question mark represents either zero or one character. This will help you catch both "woman" and its plural "women" both "color" and its spelling variant "colour" with a "u", and both "organization" and "organisation" with an "s".