to seperate words in a string use
$array1 = explode(" ", $searchstring);
If the result you mentioned is a sql query, you then need a loop like this
$sql = "select * from table1 whrere ";
foreach($array1 as $word) {
$sql .= "field1 link '%" . $word . "%' or ";
}
$sql = substr(0, strlen($sql)-3);
qry = mysql_query($sql);
etc
etc