意思差不多，但用法略有不同。 如果造句的话，我们可以说 “他在勤奋地学习。”（比较强调“学习”这个动作）或者 “他学习很勤奋。”（比较强调“很勤奋”这个状态），就看你的侧重点或想要强调的是动作还是状态。

上面都回答得太複雜了 勤奮地學習 通常是是形容他人 如 我的女友或同學在勤奮地學習 ; 學習得很勤奮 是強調學習 通常是用在自己學習得很勤奮

The translations of both sentences are "work hard", however, "勤奋地” is an adverb describing the state of studying; while "勤奋” serves as a verb complement linked by "得” in "学习得勤奋". As they serve different functions in the sentences, 地 will be put before the verb while 得 will be placed after the verb. It's kind of tricky and sometimes these two expressions can be interchangeable. e.g. 他说得很快。他很快地说。Both mean "He speaks very fast". Hope this could answer your question. :) The best.

意思是一样的，但是“得”一般后面只加一个字。勤奋地学习更加常用。