AngularJS $http url placeholders not being placed with real data

I am new to Angular, and am having an issue where my $http url placeholders are not being replaced by the actual data. What I want is for this:

"/json/:searchType/:userId"

To be replaced with this when I use my $http call:

"/json/user/123"

Instead, I get something like this, according to firebug's Net tab:

"/json/:searchType/:userId?userId=123&searchType=user"

I have tried to create a fiddle, but because I use different views and json data from a server, I'm not sure how to create something that works in the fiddle that still looks anything like what I am actually doing. I have looked at this answer, this answer, this answer, this answer, and this answer, to name a few. I'm having trouble finding a posting that isn't about $resource, or the @ notation it uses to link url params to object params though.

To explain, I'm using a service to pass the searchType and accountId params between controllers and my factory, which actually performs the $http request.

Here is my controller:

.controller('UserDetailsCtrl', ["$scope", "Search", function ($scope, Search) {
    $scope.result = Search.getUser();
}])

Here is my Factory:

.factory('Search', ["$http", "SearchCriteriaSvc", function($http, SearchCriteriaSvc) {

    var baseUrl = "/json/:searchType/:accountId";

    return {
      getUser: function () {
        return $http.get(baseUrl,
                  {params:
                      {
                        accountId: SearchCriteriaSvc.getAccountId(),
                        searchType: SearchCriteriaSvc.getSearchType()
                      }
                })
                .then(function(result) {
                  return result.data;
                }); 
      }
    }
  }])

Finally, my service:

  .service('SearchCriteriaSvc', function() {
    var searchType = "",
        userId = "";

    return {
        getSearchType: function () {
            return searchType;
        },
        setSearchType: function(value) {
            searchType = value;
        },
        getUserId: function () {
            return userId;
        },
        setUserId: function(value) {
            userId= value;
        }
    };
  })

I have tried not using the service to pass the params (just manually typing in strings) and I get the same result, so I don't think that my service is the issue, but then, I'm at a loss.

Any help would be great. Thanks!