subscience       
noun [ C ] (also sub-science) uk/ˈsʌbˌsaɪ.əns/ us/ˈsʌbˌsaɪ.əns/
 子科学
a science within a wider area of science
  Neurology is a subscience of anatomy. 神经学是解剖学的亚科学。 
 Is economics a complete science, or a sub-science? 经济学是一门完整的科学,还是一门子科学? 
 - More examples
 - This is a relatively new subscience within the field of psychology.
 - There are important differences between the various subsciences of chemistry.
 - Scientists became interested in how genes work, and this developed into a separate subscience.
 - There is a need for a science , or perhaps a subscience, of interpersonal relationships within this field of study.