如何使用jQuery过滤器选择器查找表标记td值

<table>
    <tr>
        <td>Calories </td>
        <td>TargetValue1</td>
    </tr>
    <tr>
        <td>Protein</td>
        <td>TargetValue2</td>
    </tr> 
    <tr>
        <td>Protein</td>
        <td>TargetValue3</td>
    </tr> 
<table>
    <tr>
        <td>Calories </td>