BEIJING -- China has apparently lifted efforts to block access to Google's Web site that lasted for nearly two weeks and saw ISPs hijack the search engine's domain name for several days. However, there are signs that China has implemented more sophisticated techniques to restrict access to certain types of information.

Limited access to Google's Web site resumed here on Thursday.

Blocking access to undesirable Web sites through the use of Internet protocol filters has been a common government tactic since commercial Internet access first became available here in 1995. However, authorities raised the bar earlier this week, hijacking Google's domain name and rerouting traffic to several Chinese sites--a tactic that had not been previously employed.

While access to Google's main site is now possible, pages that return search results for sensitive keywords, such as "falun gong," the spiritual movement that is banned here, remain blocked. China also continues to block access to cached copies of Web pages stored by Google.

Besides Google, the AltaVista Web search engine was also blocked in China. Earlier in the summer, Yahoo came under some criticism by human rights groups for agreeing to cooperate with the mainland Chinese government and block access to sites that contain content banned in China. But the experience with Google is the first time censors have hijacked a domain name and rerouted traffic to another Web site, observers noted.

China appears to have moved beyond simply blocking access to a Web site with IP filters and may now be employing packet filters to scan individual packets for undesirable information, said Duncan Clark, managing director at telecommunication analyst BDA China Co. Ltd.

"You can get on Google but you might not get access to the [search] results you want," Clark said.

Despite Chinese efforts to cut off access to Google, Beijing Web portal Netease.com for the last two weeks has continued to use Google's search engine as the back end for Web searches conducted on its site, without interruption. Netease.com filters those search results, the company said.