css
.right{
height: 100px;
font-size: 14px;
line-height: 100px;
text-align: -moz-center !important;
text-align: center;
vertical-align: middle;
}
.right em{
font-size: 50px;
vertical-align: middle;
}
html
<p class="right">我是左边<em>我是中间</em>我是右边</p>
效果