OASIS can not control when Google updates its data for this web site. The most recent content might not be included in their database. But the most recent content is mentioned on the Home Page so you should be able to find what you're seeking one way or another.
The Google default is to look for all keywords given. You can also use connecting words such as OR to request that either of two keywords or sets of keywords. See the Google Help Pages for more information.
Using the form will transport you out of the OASIS site and into Google. If you don't find what you're looking for, you will need to use the "Back" button of your browser.
If you edit your query on Google, leave the "site:www.oasis-nss.org" alone or you will search the entire web. (If that's what you want to do, then overwrite everything.)
The form in the side bar of each page is essentially the same as the main one on this page. You can use either one.
This form is based on one found in Google Hacks, published by O'Reilly & Associates. The feature of Google we are using is described on Google Web Serach Features page.