under a/the microscope

:  in or into a position below or beneath something

:  below or short of some quantity, level, or limit

:  in or into a condition of subjection, subordination, or unconsciousness

:  below or beneath so as to be overhung, surmounted, covered, protected, or concealed by

:  subject to the authority, control, guidance, or instruction of

:  receiving or undergoing the action or effect of

:  lower in rank or authority :  subordinate

:  an optical instrument consisting of a lens or combination of lenses for making enlarged images of minute objects

:  compound microscope

:  a non-optical instrument (such as one using radiations other than light or using vibrations) for making enlarged images of minute objects