Google Sites search

I have a number of Google Sites sites. When I start Google Sites, I get a list of my sites, and a field "Search my sites". I tried what I could do with this field, and got the following results: I tried searches with four terms, which I will call here T1, T2, T3, T4. In fact the are first names and last names of two persons. When I search for A B, I got 9 results. With "A B" I got 5 results. With C D I got 245 results, with "C D" 228. Using "A B" "C D" I got no results. With "A B" OR "C D" I got 235. With A B OR C D I got no results. I conclude that this search possibility is equal to a Google search, within your own Google Sites sites. Interesting