MEDLINE Baseline Repository
                           Frequency Counts README File
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Chemical Files (RN terms):

   -- Format of files:
       Frequency count overall in MEDLINE
       Registry Number for the Chemical
       Chemical name

   -- Chemical_freq_alpha -- Ordered by Chemical name
   -- Chemical_freq_count -- Ordered by Frequency counts (high->low)



Main Heading (MH) Files (MH terms):

   -- Format of files:
       Frequency count overall in MEDLINE
       Frequency count when starred (major) item
       Frequency count when found alone (no subheading attached)
       Frequency count when found along with one or more subheading
       MeSH Heading

   -- MH_freq_alpha -- Ordered by MeSH Headings
   -- MH_freq_count -- Ordered by Overall Frequency counts (high->low)
   -- MH_major_freq_count - Ordered by Starred Frequency counts (high->low)



SubHeading (SH) Files (qualifier terms):

   -- Format of files:
       Frequency count overall in MEDLINE
       Frequency count when starred (major) item
       Zero for now - planned future expansion
       Zero for now - planned future expansion
       SubHeading or Qualifier name

   -- SH_freq_alpha -- Ordered by Subheadings/qualifier
   -- SH_freq_count -- Ordered by Overall Frequency counts (high->low)
   -- SH_major_freq_count - Ordered by Starred Frequency counts (high->low)



Main Heading/SubHeading (MH_SH) Combination Files 
                                              (MH/qualifier combination terms):

   -- Format of files:
       Frequency count overall in MEDLINE
       Frequency count when starred (major) item
       MH/SubHeading name combination

   -- MH_SH_freq_alpha -- Ordered by MH/SH
   -- MH_SH_freq_count -- Ordered by Overall Frequency counts (high->low)
   -- MH_SH_major_freq_count - Ordered by Starred Frequency counts (high->low)

   ** Special Note:

      This counts all variants of the MH/SH combinations, applying the starred
      count only to combinations that include the starred term - for example:

      If we have an entry like the following in a citation:
         MH  - Obesity/*complications/etiology

      We include the following entries in this table:

         Obesity/*complications
         Obesity/etiology

         1|1|Obesity/complications
         1|0|Obesity/etiology