To find the short code of any database, refer to the database field guide.

..root x.yy,zz. or
root x.yy,zz.

To root into the combined index of more than one field, use the command line syntax: ..root cartilage.ab,ti. which roots into the combined Abstract and Title Fields Index and displays at the point of the term cartilage

Delete multiple results sets from your current search history by using hyphens and commas, as in the command line syntax: ..pg 5-8 (which deletes results sets five through eight) or ..pg 2,3,5 (which deletes results sets two, three, and five).

Clear all results sets from your current search history by using the command line syntax: ..pg all.

Use unlimited truncation with care; you can retrieve results with unrelated words. For example, when we enter the truncated search rat$ to retrieve comprehensive results about the animal, OvidSP does retrieve results with the words rat and rats. But it also retrieves results with the words rate, rationalize, ratify, and so forth that have nothing to do with our intended term.

The mandated wild card requires that a character be present. Therefore, you could use it at the end of a term to limit results to only those that contain the word plus the one, mandated character. For example, the search dog# retrieves results that contain the word dogs, but not those that contain the word dog effectively limiting results to only those that contain the plural form of the word.

OR Operator

The OR operator lets you retrieve records that contain any of your search terms. For example, the search heart attack or myocardial infarction retrieves records that contain heart attack, myocardial infarction or both terms. Results are all inclusive.

Combine terms using the OR operator in a qualified (fielded) search to retrieve records in which either of the terms appear in the field indicated. For example, the search (pregnancy or birth).ti. retrieves results in which either pregnancy or birth or both terms appear in the titles of the records.

Use the OR operator to combine results sets into a single set inclusive of all records from the results sets indicated. For example, the search 1 or 2 or 3 combines results from the first, second, and third sets into a single set.

AND Operator

The AND operator lets you retrieve only those records that include all of your search terms. For example, the search blood pressure and stroke retrieves only those records that contain both terms blood pressure and stroke together in the same record. Results exclude records that do not contain both terms.

Combine terms using the AND operator in a qualified (or fielded) search to retrieve records in which the terms are found in the field indicated. For example, the search (pregnancy and birth).ab. retrieves results in which both pregnancy and birth appear in the abstracts of the records.

Use the AND operator to combine two or more results sets into a single set that contains only those records that the original sets had in common. For example, the search 1 and 2 and 3 creates a set of only those records that sets one, two, and three have in common.

NOT Operator

The NOT operator lets you retrieve records that contain your first term but exclude the second term. In this way, you can restrict the scope of your results. For example, the search health reform not health maintenance organizations retrieves only those records that contain the term health reform but exclude the term health maintenance organizations.

You can also use the NOT operator to cull records from a fielded search. For example, the search (education not patient education).ti. retrieves records for which the title contains only the term education and not the term patient education.

When you use the NOT operator to combine two results sets, OvidSP removes from the first indicated results set any records that contain the term(s) indicated in the search that yielded the second results set. For example, results set 1 contains records from a search for cats. Results set 2 contains records from a search for dogs. The search 1 not 2 eliminates records from results set 1 that have any mention of dogs.

	You must use parentheses to execute this last search example. Without parentheses, this search may yield results you do not want or had not intended. OvidSP may interpret this search education not patient education.ti as either of the following.
	education.mp not patient education.ti Searches for the term education in the default (MP) fields of the database that do not have the term patient education in the Title (TI) field.
	education not patient education.mp Searches for education not patient education in the default (MP) fields of the database.

Use the NOT set and query operator carefully or you might eliminate relevant articles. For example, in the search health reform not health maintenance organizations records containing information about health maintenance organizations have been eliminated; but also, you may have eliminated records that discuss both health reform and health maintenance organizations.

ADJn Operator

The ADJ and ADJ1 operators perform the same function in a search statement: finding two terms next to each other in either order. The ADJ2 operator finds terms in any order and with one word (or none) between them. The ADJ3 operator finds terms in any order with two words (or fewer) between them. The ADJ4 operator finds terms in any order and with three words (or fewer) between them, and so on.

When applying adjacency between terms, it is helpful to know if the database in which you are searching has stop words (a list of words that OvidSP will ignore when searching for your terms). If it does, OvidSP does not count those stop words as part of the number of words that can appear between the desired terms. For example, the search physician adj5 patient would not count stop words such as a, the, or is in finding the desired result. If the database does not use stop words, OvidSP counts those words as part of the number that can appear between the desired terms. The inclusion of stop words in an adjacency threshold can reduce the number of records retrieved. In this case, you can gain best results by increasing the adjacency threshold by two or three to account for stop words. For databases that do use stop words, database field guides provides a complete list.

For example, the search physician adj5 relationship retrieves records that contain the words physician and relationship within five words of each other in either direction. This particular search retrieves records containing such phrases as physician patient relationship, patient physician relationship, relationship of the physician to the patient, and so on.

You can combine this positional operator with a fielded search. For example, the search (information adj3 retrieval).tw. retrieves records from the Text Word (TW) field that contain any phrases in which the terms information and retrieval are within 3 words of each other.

	When using the ADJn operator as part of a fielded search, it is best to combine it with word-indexed fields. To learn what fields are word-indexed, refer to the field guide of the database in which you are searching.
	Add a frequency requirement to the positional operator within a fielded search. For example, (information adj3 retrieval).tw./freq=5 retrieves records from the Text Word (TW) field that contain any phrases in which the terms information and retrieval are within 3 words of each other and occur at least five times in the record.

FREQ Operator

Syntax that applies a frequency operator requires that you qualify your term to a field, then apply the frequency you want, as in: <term>.xy./freq=n. In this syntax, xy is the two-letter field code and n represents the minimum number of times that you want your term to appear in records retrieved. Do not use spaces in this search statement. For example, the search blood pressure.tx./freq=10 retrieves only records in which the phrase blood pressure appears ten or more times in the Full Text (TX) field of the database.

The frequency operator cannot be used with multiple fields or with fields that consist of a combination of other fields (such as the Source SO field.) The following searches result in error messages. science.ti,ab./freq=3 Too many fields specified. blood.so./freq=5 The Source (SO) field consists of multiple fields.

In many OvidSP databases, the Source field consists of several fields that can identify the publication from which the record originated. These fields include such information as: journal name, publisher, issue/part, page on which a publication appears, volume and issue of a publication, year of publication, and so on.