將桌子放入投影機的框架中

首先来自投影機使用者指南的引用：

Never use a smaller font size to “fit more on a frame.” Never ever use the evil option shrink.

因此，請使用以下解決方案，风险自負！

   \documentclass[aspectratio=169, hyperref={pdfpagelabels=false}]{beamer}
%\documentclass[handout, hyperref={pdfpagelabels=false}]{beamer}
\usetheme{Madrid} 
\let\Tiny=\tiny
\usepackage{multimedia}
%\usepackage[backend=bibtex,style=authoryear]{biblatex}
\usecolortheme{whale} 
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[spanish]{babel}
\usefonttheme{professionalfonts}  
\usenavigationsymbolstemplate{} 
\setbeamertemplate{footline}[frame number]
\setbeamertemplate{frametitle}[default][center]
\setbeamersize{text margin left=2em,text margin right=2em}
\usepackage{multirow}
\usepackage{booktabs}
\usepackage[flushleft]{threeparttable}
\usepackage{siunitx}
\begin{document}
\begin{frame}[shrink=25]{Resultados}
    \centering
    \begin{threeparttable}
        \caption{Estimación de p$K_\text{a}$ para ácidos y alcoholes}\label{table:estimacion_pka_RM1}
        \begin{tabular}{lccccc}
            \toprule
             & \textbf{} & \multicolumn{4}{c}{RM1} \\  \cmidrule(lr){3-6}
             &  & \multicolumn{2}{c}{COSMO} & \multicolumn{2}{c}{SS-COSMO} \\  \cmidrule(lr){3-4}\cmidrule(lr){5-6}
             & p$K\text{a}_{\text{exp}}$\SI{298}{K} & p$K\text{a}_{\text{calc}}$ & $\Delta$p$K\text{a}$ & p$K\text{a}_{\text{calc}}$ & $\Delta$p$K\text{a}$ \\  \midrule
            \textbf{Ácidos}&  &  &  &  &  \\  
            acético & 4.75 & 2.1 & 2.6 & 4.2 & 0.6 \\  
            fluoroacético & 2.59 & -0.8 & 3.3 & -0.8 & 3.4 \\  
            fórmico & 3.75 & ref & - & ref & - \\  
            pirúvico & 2.39 & -3.0 & 5.4 & 0.7 & 1.7 \\  
            glioxílico & 3.18 & -2.3 & 5.5 & 0.4 & 2.8 \\  
            propanoico & 4.86 & 2.3 & 2.5 & 3.9 & 0.9 \\  
            butanoico & 4.83 & 2.6 & 2.3 & 4.2 & 0.7 \\  
            acrílico & 4.25 & 2.0 & 2.3 & 1.0 & 3.3 \\  
            láctico & 3.86 & 0.7 & 3.2 & 5.0 & -1.2 \\  
            benzoico & 4.2 & 1.1 & 3.1 & 1.6 & 2.6 \\  
            MAE &  &  & 3.1 &  & 1.8 \\  \bottomrule
        \end{tabular}
        \begin{tablenotes}
            \footnotesize
            \item {Comparación de p$K\text{a}$ calculados con RM1 y dos estrategias de solvatación: implícita (COSMO) y explícita-implícita(SS-COSMO). $\Delta$p$K\text{a}$ =p$K\text{a}_{\text{exp}}$-p$K\text{a}_{\text{calc}}$.}
        \end{tablenotes}
    \end{threeparttable}
\end{frame}
\end{document}

---

如果字型變得太小，可以選擇轉置表格.基於https://tex.stackexchange.com/a/32690/36296快速測試：

\documentclass[aspectratio=169, hyperref={pdfpagelabels=false}]{beamer}
%\documentclass[handout, hyperref={pdfpagelabels=false}]{beamer}
\usetheme{Madrid} 
\let\Tiny=\tiny
\usepackage{multimedia}
%\usepackage[backend=bibtex,style=authoryear]{biblatex}
\usecolortheme{whale} 
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[spanish]{babel}
\usefonttheme{professionalfonts}  
\usenavigationsymbolstemplate{} 
\setbeamertemplate{footline}[frame number]
\setbeamertemplate{frametitle}[default][center]
\setbeamersize{text margin left=2em,text margin right=2em}
\usepackage{multirow}
\usepackage{booktabs}
\usepackage[flushleft]{threeparttable}
\usepackage{siunitx}
\usepackage{adjustbox}
\usepackage{array}
\newcolumntype{R}[2]{%
    >{\adjustbox{angle=#1,lap=\width-(#2)}\bgroup}%
    l%
    <{\egroup}%
}
\newcommand*\rot{\multicolumn{1}{R{45}{0.1em}}}% no optional argument here, please!
\begin{document}
\begin{frame}[shrink=25]{Resultados}
    \centering
    \begin{threeparttable}
        \caption{Estimación de p$K_\text{a}$ para ácidos y alcoholes}\label{table:estimacion_pka_RM1}
        \begin{tabular}{lccccc}
            \toprule
             & \textbf{} & \multicolumn{4}{c}{RM1} \\  \cmidrule(lr){3-6}
             &  & \multicolumn{2}{c}{COSMO} & \multicolumn{2}{c}{SS-COSMO} \\  \cmidrule(lr){3-4}\cmidrule(lr){5-6}
             & p$K\text{a}_{\text{exp}}$\SI{298}{K} & p$K\text{a}_{\text{calc}}$ & $\Delta$p$K\text{a}$ & p$K\text{a}_{\text{calc}}$ & $\Delta$p$K\text{a}$ \\  \midrule
            \textbf{Ácidos}&  &  &  &  &  \\  
            acético & 4.75 & 2.1 & 2.6 & 4.2 & 0.6 \\  
            fluoroacético & 2.59 & -0.8 & 3.3 & -0.8 & 3.4 \\  
            fórmico & 3.75 & ref & - & ref & - \\  
            pirúvico & 2.39 & -3.0 & 5.4 & 0.7 & 1.7 \\  
            glioxílico & 3.18 & -2.3 & 5.5 & 0.4 & 2.8 \\  
            propanoico & 4.86 & 2.3 & 2.5 & 3.9 & 0.9 \\  
            butanoico & 4.83 & 2.6 & 2.3 & 4.2 & 0.7 \\  
            acrílico & 4.25 & 2.0 & 2.3 & 1.0 & 3.3 \\  
            láctico & 3.86 & 0.7 & 3.2 & 5.0 & -1.2 \\  
            benzoico & 4.2 & 1.1 & 3.1 & 1.6 & 2.6 \\  
            MAE &  &  & 3.1 &  & 1.8 \\  \bottomrule
        \end{tabular}
        \begin{tablenotes}
            \footnotesize
            \item {Comparación de p$K\text{a}$ calculados con RM1 y dos estrategias de solvatación: implícita (COSMO) y explícita-implícita(SS-COSMO). $\Delta$p$K\text{a}$ =p$K\text{a}_{\text{exp}}$-p$K\text{a}_{\text{calc}}$.}
        \end{tablenotes}
    \end{threeparttable}
\end{frame}
\begin{frame}
    \frametitle{{Resultados}}
    \centering
    \renewcommand{\tabcolsep}{0.15cm}
    \renewcommand{\arraystretch}{1.2}
    \begin{threeparttable}
        \caption{Estimación de p$K_\text{a}$ para ácidos y alcoholes}
        \begin{tabular}{lll*{11}S}
            & & & \rot{acético} & \rot{fluoroacético} & \rot{fórmico} & \rot{pirúvico} & \rot{glioxílico} & \rot{propanoico} & \rot{butanoico} & \rot{acrílico} & \rot{láctico} & \rot{benzoico} &  \rot{MAE}\\
            \toprule
            && p$K\text{a}_{\text{exp}}$\SI{298}{K} & 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2\\[1em]
            \multirow[c]{4}{*}{RM1} & \multirow[c]{2}{*}{COSMOS} & p$K\text{a}_{\text{calc}}$  & 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2\\
            && $\Delta$p$K\text{a}$  & 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2\\[1em]
            & \multirow[c]{2}{*}{SS-COSMOS} & p$K\text{a}_{\text{calc}}$  & 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2\\
            && $\Delta$p$K\text{a}$  & 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2& 4.2\\
            \bottomrule
        \end{tabular}
        \begin{tablenotes}
            \footnotesize
            \item {Comparación de p$K\text{a}$ calculados con RM1 y dos estrategias de solvatación: implícita (COSMO) y explícita-implícita(SS-COSMO). $\Delta$p$K\text{a}$ =p$K\text{a}_{\text{exp}}$-p$K\text{a}_{\text{calc}}$.}
        \end{tablenotes}
    \end{threeparttable}
\end{frame}
\end{document}