Using strict search criteria is good, but make sure you don't make them TOO strict.
For example, if you search within a specific YouTube channel, and only want videos about a specific keyword, that have more than 10,000 views and are "long" in duration... there may just be not enough of those videos that satisfy all those criteria.
Start by using fewer filters, and see if videos start getting returned.
Article ID: 182
Category: 1-Click Video Site Builder