Hi Thuy,
In Template Manager -> sj_health30 -> Options -> Global Settings
There is an option to hide main content block.
If I enable it (by choosing YES), the home page will not show (Featured Articles).
Only modules will be shown in the home page.
Now if I do a search while I am in the home page, nothing shown as a search results.
But if I open any menu (means open any other page) and do a search from there, results page appears correctly.
(I tried to attach a screenshot but attaching did not work) !!