It is possible to combine the results from different searches to produce a new result. The searches have to be from the same library. The possible modes of combination are "AND", "OR" and "BUTNOT".
EMBL: (TRYPSIN [Keyword] AND HUMAN [Organism]) 5
EMBL: (TRYPSIN [Keyword] OR HUMAN [Organism]) 423587
EMBL: (HUMAN [Organism] BUTNOT TRYPSIN [Keyword]) 423538 EMBL: (TRYPSIN [Keyword] BUTNOT HUMAN [Organism]) 44
The format of the results depends on the type of indices used. The above examples are for embl indices. If srs5.1 indices are used, the results would look like:
Q0: [embl-Keywords: trypsin] 51
Q1: [embl-Organism: human] 680320
Q2: Q0 & Q1 7
Q3: Q0 | Q1 680364
Q4: Q0 ! Q1 44
where: Q2 is Q0 AND Q1
Q3 is Q0 OR Q1
Q4 is Q0 BUTNOT Q1
For example, to search for human trypsin in the EMBL library:
Q0: [embl-Organism: human] 680320 Q1: [embl-Keywords: trypsin] 51
A new result will be added to the end of the result list:
Q2: Q0 & Q1 7
Alternatively it is possible to select results to be combined by selecting multiple results and then selecting the combination mode. Note that in this case the order of evaluation is the same as the order the items in the list from top to bottom. As seen above, the order of evaluation of the BUTNOT operator is very important.
It is possible to build up more complicated searches by using the result of one combination with another search.