search engine doesn't work properly in searching Chinese words

I found it doesn't work properly when searching for Chinese words, the engine only search the first word of each article to see they match. For example, there are two articles named 1. “关于公共服务的通知”； 2. “公共服务管理办法”. In this case, if I type in keyword "公共服务", both should be got, but actually only the 2nd is got, because the article title starts with the keyword "公共服务". This is very inconvenient when storing Chinese documents. Could you please fix this or provide any suggestions? Thanks