specialism          
noun uk/ˈspeʃ.əl.ɪ.zəm/ us/ˈspeʃ.əl.ɪ.zəm/
 [ C ] UK (US specialty)专业;专长 
a subject that someone knows a lot about
  His specialism is tax law. 他的专业是税法。 
 Synonyms: speciality (SUBJECT) specializationspecialty 
  [ U ](学科的)专业化,专门化 
limiting study or work to a few subjects
  I don't think too much specialism in schools is a good idea. 我认为在学校不宜学得过专。