Job Recruitment Website - Recruitment portal - If there is no recruitment notice at the door, can I go in and ask?

If there is no recruitment notice at the door, can I go in and ask?

Hello~Owner~

Of course, I often ask when I’m looking for a job, but generally I don’t have much hope. Try to go to the factory with recruitment notices to ask. , most companies with recruiters will post recruitment notices at the door. Thanks! ! !