My data set is very big, so I copy and paste the first 15 rows as a new exemple excel file.

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input str7 knumber str47 applicant str20 contact
"K991216" "(ARMS) HOFFMAN SURGICAL EQUIPMENT, IVF DIVISION" "FRANK  STRZEMPEK"    
"K032099" "(EMS SA) ELECTRO MEDICAL SYSTEMS"                "CYNTHIA J M. NOLTE"  
"K073284" "(EMS SA) ELECTRO MEDICAL SYSTEMS"                "SUSAN M BONAPACE"    
"K991588" "(EMS SA) ELECTRO MEDICAL SYSTEMS"                "SHEILA  HAMEON-HEYER"
"K991874" "(EMS SA) ELECTRO MEDICAL SYSTEMS"                "SHEILA  HEMEON-HEYER"
"K992504" "(EMS SA) ELECTRO MEDICAL SYSTEMS"                "CYNTHIA J.M.  NOLTE"
"K971443" "*OWNE MUMFORD USA, INC.**"                       "ROBERT E SHAW"      
"K973899" "*OWNE MUMFORD USA, INC.**"                       "ROBERT E SHAW"      
"K982275" "*OWNE MUMFORD USA, INC.**"                       "ROBERT  SHAW"        
"K983045" "*OWNE MUMFORD USA, INC.**"                       "ROBERT E SHAW"      
"K983974" "*OWNE MUMFORD USA, INC.**"                       "ROBERT  SHAW"        
"K983994" "*OWNE MUMFORD USA, INC.**"                       "ROBERT  SHAW"        
"K993385" "*OWNE MUMFORD USA, INC.**"                       "ROBERT  SHAW"        
"K150547" ".decimal, inc"                                   "KEVIN  ERHART"      
"K061440" ".DECIMAL, INC."                                  "DANIEL  BENNETT"    
end
For example, I want to subset my dataset when the applicant is decimal or DECIMAL. Notice that "decimal" is only the sub-string of the original ".decimal, inc".
My desired codes should be kind of like a program, which the inputs are these sub-strings. And I need to extract all rows that include such sub-strings, to set a new data set.