How to implement search on multiple fields limited to one content type in drupal 7
I'm not a D7 expert but I you can try with an EntityFieldQuery like this:

$query = new EntityFieldQuery();
$entities = $query-&gt;entityCondition('entity_type', 'node')
                -&gt;entityCondition('bundle', 'YOUR_CONTENT_TYPE_NAME')
                -&gt;propertyCondition('status', 1)
                -&gt;fieldCondition('YOUR_FIELD_NAME', 'value', $searchterm)
                // other conditions...
                -&gt;propertyOrderBy('title')
                -&gt;execute();
$nodes = entity_load('node', array_keys($entities['node']));