I am creating a document in LaTex and my abstract looks like

The code part is:
\section{Введение}
\textbf{Образцы:} 9 клеточных ...
\textbf{Задача:} Выполнить ...
\textbf{Методы исследования:} Анализ ...
As a result I get Задача and Методы исследований with indentation and Образцы without it. How can I insert it when?
A small update What if I need the first paragraph to be indented and others to be not?
indentfirstto get the first paragraph after sectional units indented. – Johannes_B Dec 03 '17 at 12:58\indenthas no effect after a section heading – David Carlisle Dec 03 '17 at 13:07indentfirstand it worked the way I need it. – plnnvkv Dec 03 '17 at 13:09\log_{2}. – egreg Dec 03 '17 at 13:15