It isn't just a search engine; there is an entire for-China-by-Chinese ecosystem [1]. To answer your direct question, yes, every Google online property is inaccessible within the PRC to non-registered commercial entities, and has been for the past 7 years. If you are a appropriately-registered commercial entity that can afford it, my understanding is dedicated lines (assumed monitored by the PRC) may be purchased with access to the outside world.

[1] http://www.mandarinzone.com/top-10-popular-chinese-websites/

Edit: my apologies, bad wording. Kudos to xiaoma for catching my mistake, thank you 小马 (my guess at your name in 中文）。Today, all Google properties I'm aware of are blocked. The blocking was implemented gradually across Google properties over the past 7 years. The search engine has been blocked for the past 7 years, since the beginning of the block.

Gmail wasn't blocked until later.

谢谢！ Correction added to my post.

Thanks for answering my direct question and for that link, which is exactly what I was curious about.

Even conventional VPN is not enough. The Great Firewall of China (https://en.wikipedia.org/wiki/Great_Firewall) is a mix of DNS poisoning, deep packet inspection, and traffic and usage analysis based on real time ML. It is very smart and adaptive, and will block most mainstream VPN services, including IPSEC, standard OpenVPN, SSH tunnels, (of course) SOCKS and http proxies.

Besides blocking entire sections of the net outright (like Google address blocks), poisoning controversial domains, etc, even if it can't directly inspect the traffic due to good encryption (say in the instance of OpenVPN or IPSEC), it will slowly degrade and eventually null-route your traffic over the course of minutes, depending on its judgement of the likelihood (based on packet structure and history) that your activity isn't "normal" usage.

Currently the only functional ways of getting around the GFW is VPN through stunnel (TCP OpenVPN traffic re-wrapped in TLS, thus pretending to be https traffic, and incurring triple TCP performance penalties), similar convoluted protocols like Shadowsocks, obfsproxy, and other China specific tools.

It started with the search engine and followed by all Google's services, including but certainly not limited to Blogger, Adwords, Play store, Gmail and so on. So Chinese students who were applying to foreign universities with a Gmail account would wake up one day and find they had difficulty accessing their own mailboxes. (Don't ask me how I knew it.)

Last time I checked the only Google service available now seems to be the Google Translate.

One project monitors how many popluar sites are blocked in China:

https://en.greatfire.org/analyzer

Tor is also blocked so it takes a considerable amount of effort to make it work. VPNs and other measures (socket proxy, etc.) work but they're also sinfully slow, and it breaks all the time.

The most common search engine there is Baidu: https://baidu.com. Bing has some market share as well.