R markdown / bookdown - 如何在摘要下方显示关键字？

我在 .Rmd 文件中定义了关键字，但它们在输出 PDF 中不可见。

电流输出

预期成绩

当前.Rmd

.Rmd 文件的第一行如下所示：

---
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. 

我怀疑是否base_format实际上在你的例子中做了任何工作（输出看起来与没有base_format）。自从base_format是一个论据pdf_book，考虑将您的 YAML 标头更改为

---
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
---

这将为您提供以下输出：

或者，在摘要中添加关键字：

    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