Combining results

It is possible to combine the results from different searches to produce a new result. The possible modes of combination are "AND", "OR" and "BUTNOT".

AND

eg human AND trypsin will give results containing both human and trypsin

EMBL:	 (TRYPSIN [Keyword] AND HUMAN [Organism])	 16

OR

eg human OR trypsin will give all the results containing human and all the results containing trypsin

EMBL:	 (TRYPSIN [Keyword] OR HUMAN [Organism])	 381852

BUTNOT

eg human BUTNOT trypsin will give all results containing human except those also containing trypsin. As can be seen in the example below, the more useful order "trypsin BUTNOT human", gives a very different result.

EMBL:	 (HUMAN [Organism] BUTNOT TRYPSIN [Keyword])	 381743
EMBL:	 (TRYPSIN [Keyword] BUTNOT HUMAN [Organism])	 93

For example, to search for human trysin in the EMBL library:

1. Set library = EMBL, field = Organism, text = "human", mode = word*, press "Search"
2. Set library = EMBL, field = Keyword, text = "trypsin", mode = word*, press "Search" This will produce results such as:

   EMBL:	 HUMAN*	  [Organism]	 381759
   EMBL:	 TRYPSIN* [Keyword]	 109
   

3. Select the human result with the left mouse button and use the right mouse button to invoke the popup menu. Select "Combine result" then "AND".
4. Select the trypsin result with the left mouse button.

A new result will be added to the end of the result list:

        EMBL:	 (HUMAN [Organism] AND TRYPSIN [Keyword])	 16

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.