I dont think 'replace' is as necessary as 'find' is when it comes to note-taking. This isnt intended to be a word processor. But I really need (and I believe everyone who takes a decent amount of notes would also need) the Ctrl-F functionality in notes so I can quickly go to a specific place in the note. I believe you can give a higher priority into making Ctrl-F work inside notes, atleast in the next version?

I understand the need for the find function, but the priority is determined by the voting. If this was really that desperately necessary this idea would have been in the top 10.

Same here. If i really want to replace i can paste the text to some editor and do the job. But searching inside the note is something i often miss.

RUS: Добавть возможность поиска непосредственно в определённой заметке (например, по ctrl+F). Это было бы очень удобной возможностью, т.к. если заметка большая, то глобальный поиск выделяет лишь перевое совпавшее слово в данной заметке, а я хочу видеть все совпадения. Поэтому данная функциональность поиска всех совпадений (и их подсвечивания) в определённой заметке была бы весьма полезной.

This is already on the roadmap: http://roadmap.cintanotes.com/topic/3169-search-and-replace-inside-of-note-edit-dialog/
Also if you select some text in the editor and press F3/Shift+F3, you can navigate to next/previous instance of the same text.