最后通过在http://getbootstrap.com/customize/上摆弄“@grid-float-breakpoint”来解决如何改变折叠宽度的问题。

转到bootstrap.css(也是最小版本)的2923行，将@media screen和(min-width: 768px){改为@media screen和(min-width: 1000px) {

所以代码最终会是:

@media screen and (min-width: 1000px) {
  .navbar-brand {
    float: left;
    margin-right: 5px;
    margin-left: -15px;
  }
  .navbar-nav {
    float: left;
    margin-top: 0;
    margin-bottom: 0;
  }
  .navbar-nav > li {
    float: left;
  }
  .navbar-nav > li > a {
    border-radius: 0;
  }
  .navbar-nav.pull-right {
    float: right;
    width: auto;
  }
  .navbar-toggle {
    position: relative;
    top: auto;
    left: auto;
    display: none;
  }
  .nav-collapse.collapse {
    display: block !important;
    height: auto !important;
    overflow: visible !important;
  }
}

除了@Skely answer，要使导航栏内的下拉菜单工作，也添加他们的类被覆盖。最终代码如下:

    @media (min-width: 768px) and (max-width: 991px) {
        .navbar-nav .open .dropdown-menu {
            position: static;
            float: none;
            width: auto;
            margin-top: 0;
            background-color: transparent;
            border: 0;
            -webkit-box-shadow: none;
            box-shadow: none;
        }
        .navbar-nav .open .dropdown-menu > li > a {
            line-height: 20px;
        }
        .navbar-nav .open .dropdown-menu > li > a,
        .navbar-nav .open .dropdown-menu .dropdown-header {
            padding: 5px 15px 5px 25px;
        }
        .dropdown-menu > li > a {
            display: block;
            padding: 3px 20px;
            clear: both;
            font-weight: normal;
            line-height: 1.42857143;
            color: #333;
            white-space: nowrap;
        }
        .navbar-header {
            float: none;
        }
        .navbar-toggle {
            display: block;
        }
        .navbar-collapse {
            border-top: 1px solid transparent;
            box-shadow: inset 0 1px 0 rgba(255,255,255,0.1);
        }
        .navbar-collapse.collapse {
            display: none!important;
        }
        .navbar-nav {
            float: none!important;
            /*margin: 7.5px -15px;*/
            margin: 7.5px 50px 7.5px -15px
        }
        .navbar-nav>li {
            float: none;
        }
        .navbar-nav>li>a {
            padding-top: 10px;
            padding-bottom: 10px;
        }
        .navbar-text {
            float: none;
            margin: 15px 0;
        }
        /* since 3.1.0 */
        .navbar-collapse.collapse.in { 
            display: block!important;
        }
        .collapsing {
            overflow: hidden!important;
        }
    }

演示代码

现在Bootstrap 4.4支持它

navbar-expand-sm 

在Bootstrap 3 . less源代码中，变量中定义了一个变量。Less被称为@grid-float-breakpoint，它有以下有用的评论:

//**Point at which the navbar becomes uncollapsed
@grid-float-breakpoint: @screen-sm-min;

匹配的@grid-float-breakpoint-max值设置为- 1px:

//**Point at which the navbar begins collapsing
@grid-float-breakpoint-max: (@grid-float-breakpoint-max - 1);

解决方案:

所以只需将@grid-float-breakpoint的值设置为1000px，然后重新构建bootstrap。较少进入bootstrap.css:

e.g.

@grid-float-breakpoint: 1000px;

在bootstrap3中，将这个变量@grid-float-breakpoint更改为您需要的值。默认值是768px

对于Bootstrap 3.3，这是你唯一需要的代码:

@media (min-width: 768px) and (max-width: 1000px) {
   .navbar-collapse.collapse {
       display: none !important;
   }
   .navbar-toggle{
        display: block !important;
   }
   .navbar-header{
        float: none;
   }
}