1. No is a determiner. We use no before singular (countable and uncountable) nouns and plural nouns.
No means the same as not a or not any, but we use no:
(a) at the beginning of a sentence
(b) when we want to make the negative idea emphatic.
a.
- No cigarette is completely harmless. (NOT Not any cigarette…)
- No beer? How do you expect me to sing without beer?
- No tourists ever come to out village.
b.
- I can’t get there. There’s no bus. (More emphatic than There isn’t a bus)
- Sorry I can’t stop. I’ve got no time.
- There were no letters for you this morning, I’m afraid.
2. Nobody, nothing, no-one and nowhere are used in similar ways to no.
Compare:
- Nobody came. (NOT Not anybody came)
- I saw nobody (More emphatic than I didn’t see anybody)
3. We only use no immediately before a noun. In other cases we use none (of).