11. The method according to claim 8 , wherein, when the user input is the Pinyin input, the step A specifically comprises: A1′: receiving the Pinyin input by the user, querying the recommended word database according to input Pinyin to acquire guiding Chinese character(s) corresponding to the input Pinyin and using the guiding Chinese character(s) as a search keyword.
8. A recommendation method for search input, comprising: A: acquiring a search keyword according to a user input; B: querying a search tree storage unit according to the search keyword to acquire address information of recommended word(s); wherein the search tree storage unit is configured to store Chinese characters in a tree data structure, wherein each node in the tree stores one Chinese character and the address information of the recommended word(s) containing the Chinese character; C: querying a recommended word database according to the address information of the recommended word(s) to acquire the recommended word(s) and then suggesting the recommended word(s) to the user, wherein the recommended word database is configured to store the recommended word(s); wherein the user input is Pinyin input or Chinese character(s) input; wherein when the user input is the Chinese character(s) input, the step A further comprises: A1: receiving Chinese character(s) input by the user and using the input Chinese character(s) directly as a search keyword; the step B further comprises: B1: querying the search tree storage unit to find address information of primary recommended word(s) with the input Chinese character(s) as a prefix at a node corresponding to the last character of the input Chinese character(s); wherein, after the step B1, the method also comprises: B2: judging whether the number of corresponding primary recommended word(s) is bigger than or equal to a preset threshold value according to the address information of the primary recommended word(s); and if yes, executing the step C; otherwise, querying the recommended word database based on the address information of the primary recommended word(s) to acquire the primary recommended word(s) and executing a step B3; B3: extending the primary recommended word(s) to acquire address information of the extended recommended word(s).