自定义的粗体和斜体等 .bst 文件不起作用

Question

我正在使用 overleaf 编写文档。我在agsm引用样式的 overleaf 项目中上传了一个自定义 .bst 文件。我需要将“et. al.”加粗并加斜体。我尝试通过将et~al.agsm .bst 文件中的所有内容编辑为来实现这一点\textbf{\textit{et~al.}}。编译后，斜体有效，但粗体部分无效。需要帮助。

我的序言：

\ProvidesPackage{preamble}


\usepackage[english]{babel}
\usepackage{geometry}
\usepackage{amsmath}
\usepackage{graphicx}
%\usepackage{epstopdf}
\usepackage{color}
\usepackage{titlesec}
\usepackage{fancyhdr}
\usepackage{emptypage}
\usepackage{float}
\usepackage[export]{adjustbox}
\usepackage{diagbox}
\usepackage{caption}
\usepackage[labelformat=simple]{subcaption}
\renewcommand\thesubfigure{(\alph{subfigure})}
%\usepackage{enumerate} % not along with enumitem
\usepackage{enumitem}
\usepackage{epigraph}
\usepackage{afterpage}
\usepackage[intoc]{nomencl}
\usepackage{tabularx}
\usepackage{array}
%\usepackage{booktabs,floatrow}
\usepackage{longtable}
\usepackage{cite}
\usepackage{url}
\usepackage{natbib}
\usepackage{apalike}
\usepackage{xfrac}
%\usepackage[title,titletoc]{appendix}
\usepackage[linktocpage=true]{hyperref}
\usepackage{multirow}
\usepackage{textcomp}
\usepackage{csquotes}
%\usepackage{etoolbox}
\usepackage{amssymb}
\usepackage{siunitx}
\usepackage{pbox}
\usepackage{makecell}
\usepackage{pgfgantt}
%\renewcommand{\bibsection}{\chapter{\bibname}}
%Page Layout
\geometry{
    a4paper,
    %total={170mm,257mm},
    left=0.7in,
    right=0.7in,
    top=1in,
}
\renewcommand\theadalign{bc}
%Modifying Headings
\makeatletter
\titleformat{\chapter}[display]
{\normalfont\LARGE\bfseries\centering}{\MakeUppercase\@chapapp\ \thechapter}{1pt}{\LARGE}
\makeatother
\titlespacing*{\chapter}{0pt}{-50pt}{0pt}
\usepackage[english=nohyphenation]{hyphsubst}
%Paragraph and line spacing
\setlength{\parindent}{4em}
\setlength{\parskip}{1em}
\renewcommand{\baselinestretch}{1.5}

%Header Footer
\pagestyle{fancy}
\fancyhf{}
\setlength{\headheight}{15pt}
\fancyhead[LE,RO]{\leftmark}
\fancyfoot[RE,LO]{\rightmark}
\fancyfoot[LE,RO]{\thepage}
\renewcommand{\headrulewidth}{2pt}
\renewcommand{\footrulewidth}{1pt}

%Image

%\graphicspath{{C:\Users\TAMOGHNA\Desktop\latex}}
%\DeclareGraphicsExtensions{.eps}
\renewcommand{\epigraphsize}{\normalsize}
\setlength{\epigraphwidth}{0.7\textwidth}
\renewcommand{\textflush}{flushright}
\renewcommand{\sourceflush}{flushright}
\let\originalepigraph\epigraph 
\renewcommand\epigraph[2]{\originalepigraph{\textit{#1}}{\textsc{#2}}}

%To insert blank page
\newcommand\blankpage{%
    \clearpage
    \thispagestyle{empty}%
    \addtocounter{page}{-1}%
    \mbox{}%
    \clearpage}

%ToC Name Change
\addto\captionsenglish{\renewcommand*\contentsname{TABLE OF CONTENTS}}

%LoT, LoT Name change
\addto\captionsenglish{\renewcommand{\listfigurename}{LIST OF FIGURES}}
\addto\captionsenglish{\renewcommand{\listtablename}{LIST OF TABLES}}
\addto\captionsenglish{\renewcommand{\bibname}{REFERENCES}}

%nomenclature
\makenomenclature

%Table formatting array
\newcolumntype{P}[1]{>{\centering\arraybackslash}p{#1}}
%\floatsetup[table]{objectset=centering,capposition=top}

%---------------------------------------------------------%
%Appendices
\addto\captionsenglish{\renewcommand*\appendixname{APPENDIX}}
%---------------------------------------------------------%
%Acronyms
%Acronyms

%---------------------------------------------------------%
%Slash Frac 
\usepackage{xfrac}

我的主体：

\documentclass[a4paper,,twoside]{report}
\usepackage{preamble}
\usepackage{import}
%---------------------------------------------------------%
\raggedbottom 

\begin{document}
\import{titlematter/}{frontpage.tex}
\pagenumbering{roman}

%---------------------------------------------------------%
%ToC
\tableofcontents


\chapter{INTRODUCTION}
\pagenumbering{arabic}
\setcounter{page}{1}
\pagestyle{fancy}
\import{./}{introduction.tex}

\cleardoublepage
\addcontentsline{toc}{chapter}{\numberline{}REFERENCES}
\bibliographystyle{agsm_IB}
\bibliography{irbref}
\end{document}

这是一个很大的文档，因此我将每一章都写在单独的 tex 文件中。