Boolean operators form the basis of mathematical sets and database logic. Using these terms to combine concepts and keywords in your search will assist you in performing a transparent, reproducible, and thorough search. Boolean operators include AND
, OR
, and NOT
.
Proximity and adjacency operators allow you to search for words next to or near each other. These operators vary from database to database, so always consult the each databases's help section to find out how to use proximity and adjacency operators within that database.
Proximity/Adjacency Operators |
Example |
"Adjacency" or "Near" Operators: Nx finds the words within x words of one another, regardless of the order in which they appear |
(healthcare OR "health care") N5 reform |
"Next", "Precedes", or "Within" Operators: Wx finds the words within x words of one another, in the order in which you have entered them | oil W3 (disaster OR spill OR contamination) |
Selected databases and their proximity operators:
Database |
Adjacency/Proximity Operators Allowed |
Format |
---|---|---|
CINAHL (EBSCOhost) | Yes, "Near" and "Within" | term Nx term; term Wx term |
The Cochrane Library | Yes, "Near" and "Next" | term NEAR/x term; term NEXT term |
Embase | Yes, "Near" and "Next"> | term NEAR/x term; term NEXT/x term |
ERIC (EBSCOhost) | Yes, "Near" and "Within" |
term Nx term; term Wx term |
Global Health (Ovid) | Yes, "Adjacency" | term ADJx term |
Medline (Ovid) | Yes, "Adjacency" | term ADJx term |
PsycINFO (EBSCOhost) | Yes, "Near" and "Within" |
term Nx term; term Wx term |
PubMed (NCBI) | No | N/A |
Scopus |
Yes, "Within"* and "Precedes" *Note that in Scopus, order does not matter when using "Within," but order matters when using "Precedes" |
term W/x term; term PRE/x term |
Web of Science | Yes, "Near" | term NEAR/x term |