It is the NIH genetic sequence database, an annotated collection of all publicly available DNA sequences. A new release is made every two months.
Expression profiling contains thousands of data points per run.
The file contains over 11 million citations dating back to the mid-1960's. The resulting abstracts are analyzed statistically to extract and highlight the most important findings in the abstracts. The analysis includes co-occurance, proximity checking and weighting based on total term frequencies.