import re

s = '''<dt>
    <a href="#profile-experience" >Past</a>
</dt>
<dd>
    <ul class="past">
        <li>
            President, CEO &amp; Founder <span class="at">at</span> China Connection
        </li>
        <li>
            Professional Speaker and Trainer <span class="at">at</span> Edgemont Enterprises
        </li>
        <li>
            Nurse &amp; Clinic Manager <span class="at">at</span> <span>USAF</span>
        </li>
    </ul>
</dd>​​​​​'''

ul = re.findall('<dt>.*?Past.*?</dt>.*?<dd>.*?<ul class="past">.*?((<li>.*?</li>\s*)+).*?</ul>.*?</dd>', s, re.DOTALL | re.MULTILINE)
rs = re.findall('<li>.*?</li>', ul[0][0], re.DOTALL | re.MULTILINE)

for li in rs:
    print li