[{"_id":ObjectId("5a934e000102030405000000"),"from":"1970-01-01","to":"1970-01-05"},{"_id":ObjectId("5a934e000102030405000001"),"from":"2017-04-18","to":"2017-04-23"},{"_id":ObjectId("5a934e000102030405000002"),"from":"2018-01-29","to":"2018-01-30"},{"_id":ObjectId("5a934e000102030405000003"),"from":"2018-01-02","to":"2018-01-08"}]

db.collection.find({from:{$regex:"2018-01",}})