<input type="text" class="form-control" ng-model="value1" id="textCI" placeholder="C.I." >

buscarCI(){
    let query=null;
    query=this.servicio.getUsuarioFiltro(this.ResultCI);
    query.snapshotChanges()
      .map(changes=>{
        return changes.map(c=>({key:c.payload.key, ...c.payload.val()}))
      }).subscribe(contactos =>{
        this.contactos=contactos
      });
  }