英和和英

an in‐depth study

profound studies

to make a deep study of―go deep into―dive into―delve into―a subject

to go deep into a subject―dive into a subject

a thorough study

plunge into studying

a course of study

a course of study

a course of study

under study

an exhaustive study

an exhaustive study

a study

a fusty study

diligent study

to make a profound study of

extramural studies

to study hard

to study hard

immerse oneself in study

do research

a subject of study

a subject of study

to learn thoroughly

thoroughgoing research

to go through a long course of study

to go through a long course of study―make a long study of a subject

a close study

assiduous research

thorough research