Definition
To focus all one's energy and effort on a specific task.
努力工作，全力以赴
I need to get my head down and finish this proposal to meet the deadline.
我需要专心完成这份提案以赶上截止日期。
The exams are coming up, you should really get your head down and study.
考试快到了，你真的应该专心读书。
In the final stage of the project, we all need to get our heads down and get everything finished.
在项目的最后阶段，我们都需要专心完成所有事情。