Flow of information during data searching in the simple and advanced modes. A user specifies a query (e.g. hnf1a AND homo sapiens[Organism]) and a database, against which the query will be executed (e.g. Nucleotide). The search GenBank calls the ESearch tool and passes the name of the database, user’s query and additional parameters as input arguments. The ESearch tool returns the list of identifiers for records that satisfy the user’s query. The search GenBank calls the ESummary tool, which is parameterized by messages provided by search GenBank, ESearch tool, and explored databases. The ESummary returns a list of records (their summaries) satisfying the user’s query. After a short review of returned records, the user decides to see full details of one of them (e.g. UID 260593720). He/she interactively triggers a call of EFetch tool, which retrieves data from the database for a passed record identifier UID and presents details of the chosen record on the search GenBank web page.