public function search(Request $request)
    {

        $k = $request->query()['k'] ?? '';
        if(!$k)return redirect()->back()->with(['msg'=>__('请输入关键词'), 'alert'=>'danger']);
        $searchlist = Article::where('title', 'like', '%'.$k.'%')->orWhere('content','like','%' . $k . '%')->paginate(30);
        return view('search.index', compact('k', 'searchlist'));
    }