As a workaround, you can use search operators on Google.com to search for content specifically on your blog. For example:
site:yourblog.blogspot.com KEYWORD KEYWORD
Update, 1/22: Thanks to everyone for all the detailed reports on the gaps in our search coverage. Both the Blogger and BlogSearch teams are working now on completing a full resolution of the issue, and we anticipate it will be fixed in the next several weeks.
Update, 3/28: This is now resolved. Thanks for your patience.
Update, 4/25: We've recently identified a few different cases where search results aren't displaying accurate information. We're re-opening this issue and will update this post as soon as we have more info to share.
Update, 3/28: This is now resolved. Thanks for your patience.
Update, 4/25: We've recently identified a few different cases where search results aren't displaying accurate information. We're re-opening this issue and will update this post as soon as we have more info to share.