Google Search is also partially blocked
We just put out a story on GMail being partially blocked in China. It turns out that Google Search is suffering the same treatment. The table shows an overview of the IP addresses that are currently returned when looking up www.google.com or www.google.com.hk from China. One out of 13 is blocked. The IP address is chosen randomly when you first access google.com. If you are unlucky, a blocked IP address is chosen and you can't access Google. One quick way around it is to go to some other Google domain such as google.co.uk or google.ca.
The IP addresses used by Google Search and GMail are similar so perhaps this is just a mistake. But it's also possible that it's intentional and that even the basic Google Search will become unreliable in China from now on.