In general, a custom search engine searches across a set of sites you specify. However, you can configure your custom search engine to search the whole web. In this case, however, your results are unlikely to match those returned by Google Web Search, for several reasons:
- Even if a custom search engine is configured to search the entire web, it’s designed to emphasize results from your own sites.
- Custom Search Engines configured to search the entire web are limited to a subset of the total Google Web Search corpus.
- Your custom search engine doesn’t include Google Web Search features such as Oneboxes, real-time results, universal search, social features, or personalized results.
- If your custom search engine includes more than 20 sites, the results may differ from the results of a 'site:' search on Google.com and your CSE may sometimes display fewer results.
If you'd like to see more complete results in your custom search engine, try the following option:
- In the Basics tab of the control panel, under Sites to search, make sure to include no more than 20 unique sites. Each unique domain you add is counted towards this total; pages within these domains aren't. If you happen to add more than 20 unique sites, your CSE may sometimes display fewer results.
- Add refinements inside your search engine.