Yes, discover would be the one to use.

https://api.themoviedb.org/3/discover/movie?api_key=###&primary_release_date.gte=2018-08-13&primary_release_date.lte=2018-08-13

There's some other filters you can apply like release region and release type. These are outlined in the documentation.

Thank you very much for the answer, but I need films that were not released in 2018 and in any other year, when but necessarily today. For example 2003-14-08, 2007-08-14, 1986-08-14 and so on. Please read the question carefully!

You can enter any date you wish.... But to get all the days, you would have to query every year you want results from. There is no "day" query.

Thanks a lot. Will have to parse the code. I thought there was something like a like-query on the release_date column. In any case, thanks again.