Perhaps you should try some spelling variations:
teaching learning » machine learning
rent teaching » text teaching, current teaching, remote teaching
chen yiqun » chen yun, shen yijun
dong yang » dong hoang, wang yang, dan yang
yang yang » wang yang, wang yan
chong yun » chang yun, hong yu, chen yun
yang hua » wang hua, yang hui, ying hua
hua rent » hua ren

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: dong yang yang hua rent teaching learning ((chong yun) OR (chen yiqun)) ;~.
• Adding a wildcard symbol may retrieve word variants: dong yang yang hua rent teaching learning ((chong yun) or (chen yiqun)) ;*.