Derwent subscriber

In order to access the Derwent fragmentation code, and also to access Derwent documentation abstracts with detailed Markush and chemical summaries, it is necessary to be a Derwent subscriber. Derwent subscriptions are widespread among corporations in North America, Europe, and Japan. The Derwent fragmentation data is not available to academic institutions or other nonsubscribers at this time. 

World Patents Index DIALOG, ORBIT, Questel, STN Derwent Information Ltd. international limited bibliographic data patent families comprehensive English language abstracts of basic and some equivalent granted patents polymer and chemical stmcture indexing for subscribers drawings... 

World Patents Index / APIPAT ORBIT Derwent Information Ltd. American Petroleum Institute international limited bibhographic data patent families comprehensive English language abstracts of basic patents aU Wodd Patents Index and APIPAT indexing for subscribers... 

The WPIM file corresponds to Derwent World Patents Index (DWPI) online file, and therefore includes documents from all of the countries that Derwent normally covers. Indexing for WPIM began in 1987, and since 1987, Derwent has double indexed all chemical patents with both the fragmentation codes and WPIM indexing. Specific structures are indexed if they are not part of a Markush structure in the same patent document. Polymers are not indexed in detail in the WPIM database. Polypeptides of 10 or more amino acids are indexed in a separate non-Markush database and are not included in WPIM. All four online services that carry the DWPI also have the WPIM accession numbers. WPIM indexes patents from all countries in the Derwent database, but it is available to subscribers only. 

Derwent s file, too, is scheduled to be installed at STN by the end of 1994. It contains all patents from 1987 onward in the fields of pharmacy, agriculture and chemistry. Both systems present a valuable supplement to each other. Unfortunately, Derwent is only available to the subscribers of the printed Derwent services (Sect. 7.4). 

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