Quoted phrase searches return results where the terms within the quotation marks appear adjacent to each other in the same order they are entered. Proximity searches allow more lenient searches where the word order can be changed and the terms do not have to be adjacent to each other.
To execute a proximity search, enter a quoted phrase, followed by a tilde, followed by the number of word position changes allowed. For example:
“lung cancer”~4Proximity is determined by word positions and the number of position changes allowed. Proximity is designated by the number following the tilde. Words appearing between the quoted search terms, as well as word order transposition, contribute to the position changes allotted. When you search “lung cancer” what you’re really searching is “lung cancer”~0, where lung and cancer must appear in exactly that order. Searching “lung cancer”~4 will return some of the following results:
“cancer of the lung”
“cancer in the lung”
“lung and breast cancer”
“lung disease and breast cancer”
“cancer therapy in lungs”In the above example, “cancer of the lung” is a result returned from the search “lung cancer”~4. Lung and cancer swapped places where cancer moved left 1 position and lung moved right 1 position. The word order transposition used 2 of the specified 4 position changes allowed because lung and cancer each moved one time. The words of the appearing between the quoted search terms use the remaining 2 available position changes.
Proximity search can be used with any length of quoted phrase and the position changes allowed, specified by the number following the tilde, is boundless. However, searching for “lung cancer”~100 is similar to conducting a search on lung AND cancer where lung and cancer will appear within the same record but the relationship between the terms will be less strict than “lung cancer”~4 or “lung cancer”~10. For more strict results keep the number following the tilde low. For more flexible results increase the number following the tilde.