如何使用通配符在Mongodb上进行搜索?

For example if my keyword is "all", I would like MongoDb to return all the documents in the given field containing the words "all" like "edgar allan poe" or "whitney hall". How do I do that in MongoDb? I've been stuck here for days so any help would be greatly appreciated :)For example if my keyword is "all", I would lik