Note: these are the partial results for collocates of chair in FICTION (left) and ACADEMIC (right) in the COCA corpus. Another search (in another corpus) will of course yield different results, but the general concepts remain the same.
 

SEC 1: FICTION: 104,900,827 WORDS   1 
 

  WORD/PHRASE
  3 

TOKENS 1
  4 
TOKENS 2
  5 
PM 1
  6 
PM 2
  7 
RATIO
  8 
1   WING 103 0 0.98 0.01 98.2
2   FEET 196 2 1.87 0.02 96.2
3   KITCHEN 266 3 2.54 0.03 87.4
46   DESK 540 18 5.15 0.17 29.6
SEC 2: ACADEMIC: 103,421,981 WORDS   2 
    WORD/PHRASE  9 
4
TOKENS 1
4
TOKENS 2
4
PM 1
4
PM 2
4
RATIO
4
1   DIVISION 52 1 0.50 0.01 52.7
2   ENGINEERING 51 1 0.49 0.01 51.7
3   RISE 44 1 0.43 0.01 44.6
29   STUDIES 26 7 0.25 0.07 3.8

1. The number of words in SECTION(s) 1 of the search form
2. The number of words in SECTION(s) 2 the search form
3. The rank-ordered list of words or phrases in SECTION 1. Click on the word or phrase to see the "Keyword in Context" display.
4.
The raw frequency of the item, in SECTION 1
5. The raw frequency of the item, in SECTION 2
6. The normalized frequency in SECTION 1 (tokens per million words)
7. The normalized frequency in SECTION 2 (tokens per million words)
8. The relative percentage in the two sets of sections. For example, in this case desk (the last entry on the left) occurred (per million words) as a collocate of chair 29.6 times as much in FICTION as in ACADEMIC. (Note: When there are no tokens from SECTION 2, the percentage is the normalized frequency in SECTION 1 divided by .1 -- to avoid division by zero)
9. The same as 3-8 above, but for the entries in SECTION 2.

Note that in the example above, the entries are sorted by the "score", which is a function of the ratio in the two sections of the corpus. But if you just want to see which are the most frequent strings with each section (regardless of what is happening in the other section), then select OPTIONS / [SORT BY] = [FREQUENCY] in the search form.