美国博士需要上课吗？
1. American PhD is different from Chinese/British PhD in terms of coursework， but I would not say any less ‘formal’ - it really depends on the program and department you are in. In general， an MS is considered a terminal degree with some exceptions (e.g. IT)；it takes at least three years to complete， including course work， passing qualifying exams， writing a dissertation proposal（and if need be， drafting a section of your dissertation）， and finally defending and writing up your dissertation. There may or may not be any other forms of assessment besides the written dissertation – this varies by department. The expectation is that you will have been actively engaged in research throughout and that you will continue to make contributions to knowledge as you progress through your studies until you defend your dissertation and thus gain your PhD.
In contrast， for many European universities， a master's degree IS considered a precursor to a doctoral level degree and therefore students expect to do some form of practical application or project based on their Masters research findings before proceeding onto a PhD. I know a number of international students who come here with such degrees where the expectation was that they would have finished all their course requirements after one year and spend another year researching and writing up， but found out shortly after arrival that due to departmental policies， they had to stay for two full years of study and research just to finish up！ So it does depend…
2. As someone mentioned above， most US Phd programs will admit you on an F1 VISA which makes them very strict about how involved you can be in the workplace outside of school， especially while you are in your first few years. Usually there will be no problem finding part time positions once you have received your degree and are on an OPT work visa， but looking for jobs before then is more difficult. You are allowed to accept offer of employment from companies， but should have already made arrangements to transfer funds to cover living expenses in case you