If you are in Firefox
Right-click on the toolbar and choose “New Bookmark”.
In the New Bookmark dialog box, give a reasonable name. Say, “Google Instant Search” and at the Location field, copy-paste the following Javascript code:
javascript:function()%7B%20p=prompt(‘Search%20term:’,”);%20if(p)%7B%20document.location.href=’http://www.google.com/search?as_qdr=n10&q=’%20+%20escape(p)%7D%20%7D)();
Click on the ADD button.
For Google Chrome
Click on the star sign at the right side of the address bar and select Edit.
Similarly, put the name and the Javascript code at the location in right boxes and selectBookmark bar as saving location, then click OK.
Clicking on the bookmarklet shows you a box asking you to put your keyword. Put your keyword and hit the OK button. It will show all the results against your keyword at Google search engine in last 10 mins.
You can change the time duration by editing the above Javascript code. Just change the value of as_qdr. Here n10 means it will show the results of past 10 mins. If you want that for past 20 mins then put n20 instead of n10.