An Introduction to Computer Searching of
Chemical Abstracts
STN International Version
STN Proximity Operators
Operator |
Function |
(W) or space |
Terms must be adjacent and in the order specified |
(nW) |
Terms must be adjacent and in the order specified with n or fewer intervening terms |
(A) |
Terms must be adjacent but in any order |
(nA) |
Terms must be adjacent but in any order with n or fewer intervening terms |
(L) |
Terms must occur in same information unit (e.g. title, keyword, or index) |
Examples in CA File
You Enter |
System Response |
s gas (w) chromatography |
L1 20954 GAS (W) CHROMOTAGRAPHY |
s gas (a) chromatography |
L2 44392 GAS (A) CHROMATOGRAPHY |
s gas (l) chromatography |
L3 48054 (L) CHROMATOGRAPHY |
s gas and chromatography |
L4 48922 GAS AND CHROMATOGRAPHY |
Tips
- Spacing around proximity operators is optional
- Both the letter for the proximity operator and the parantheses are required for all proximity
operators except (w). In fields that have individually indexed terms, you can use a space
instead of a (w).