Table - matching_text with two fields

rowid number(10)
text_field varchar2(100)

text_field contents:

"dengue fever causes lever malfunction headache and vomiting"
"dengue headache and vomiting fever causes lever malfunction"

i have a search string "fever yellow malfunction"

if any of the word in the search string match with the text_field then i have to calculate the percentage of the matching words.