The "Narrow Search" feature, shown on the left side of the search results page, is provided to help you further refine your search results.

1) Narrow Search by Category ①: The "Category" list on the left displays all categories and sub-categories found within your search results. If you click on any of the categories, just the search results within that category will be displayed.
2) Narrow Search by Jurisdictional Level ②: The "Jurisdictional Level" list, also on the left, shows all jurisdictional levels found within the search results. Clicking on any of these will display only the search results under that level.
3) Narrow Search by Effective Area ③: The "Effective Area" will filter your results in a similar way, this time by reference to the geographical area in which the document has effect.

For example, a search results page will be displayed if you input "individual income tax" in "Title" input box and submit the search. If you then select "Intellectual Property Rights" in the Category list, "Normative Documents" in the Jurisdiction Level list and "National" in Effective Area list, you will see the single search result that matches these categories. Alternatively, you can select any of the terms in the "Filter Search Terms" ④ area to continue the search.