如何从C＃中找到活动目录中的用户？

I'm trying to figure out how to search AD from C# similarly to how "Find Users, Contacts, and Groups" works in the Active Directory Users and Computers tool. I have a string that either contains a group name, or a user's name (usually in the format firstname middleinitial [if they have one] lastname, but not always). Even if I do a seperate query for groups vs. users, I can't come up with a way to search that captures most user accounts. The Find Users, Contacts, and Groups tool brings them back almost every time. Anyone have any suggestions?I'm trying to figure out how to search AD from