Q:

R markdown / bookdown - how to display keywords below an abstract?

I defined keywords in the .Rmd file, but they are not visible in the output PDF. 

Current Output

Expected results

Current .Rmd
First lines of .Rmd file looks as follows:
---
title: "No keywords within the output file"
abstract: "This is sample text for abstract. Generally speaking, I would like to show keywords list below an abstract (as in case of the linked example)"
keywords: "keywordA, keywordB"
author: "Mateusz Kędzior"
output: 
  bookdown::pdf_document2:
    keep_tex: true
    number_sections: yes
    toc: false
base_format: rticles::elsevier_article
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

## Elsevier article

This is an R Markdown document.

I'm trying to prepare an Elsevier article. 

A:

I wonder if base_format is actually doing any work in your example (the output looks the same with and without base_format).  Since base_format is an argument to pdf_book, consider changing your YAML header to
---
title: "No keywords within the output file"
author: 
- name: "Mateusz Kędzior"
abstract: "This is sample text for abstract. Generally speaking, I would like to show keywords list below an abstract (as in case of the linked example)"
keywords: "keywordA, keywordB"
output: 
  bookdown::pdf_book:
    keep_tex: true
    number_sections: yes
    toc: false
    base_format: rticles::elsevier_article
---

which gives you the following output:

Alternatively, add keywords to the abstract:
    abstract: "This is sample text for abstract. Generally speaking, I would like
 to show keywords list below an abstract (as in case of the linked example) \\par
 \\textbf{Keywords:} a, b"

to get

