Use at least 3-4 words in your query that are relevant. For example "vpn" will give poor, non-specific results. But "configure xauth vpn" will provide very targeted results. NOTE: Support Search searches almost the entire website, not just the Knowledge Center. You can filter the results to a particular source using the By Source filter on the left-side of the search resuts page.
Juniper Networks - Knowledge Base. Internet Engineering Task Force.