Not "plagiarism", though Russian Internet sites often erroneously use this term - even when Russian system Antiplagiat (that is broadly used to check the works out on coincidences) doesn't apply it. The official sources rather use the "correct borrowing" term, and it concerns the excerpts and quotations followed by proper sources (for example, you can check that document of Lomonosov Moscow State University describing verification procedure of graduate works and dissertations of students and postgraduates of Journalism faculty - it's on Russian, but I suppose that you can understand it since it's your mother tongue).