Why is there a 上 in this sentence? How does it change the meaning? Ie, what's the difference between 工作的东西 and 工作上的东西? When should 工作上 be used as opposed to 工作?
Actually, there's not so much difference.
工作上的东西,工作的东西both mean something related to your work.
上actually doesn't mean too much , Chinese language is not that strict as English, you don't have to understand every word.
More examples about
-孩子,你在看什么?(Son, what' are you viewing?)
-妈妈,我在看学习上的书(Mom, I am just viewing some academical books)