[CentOS] how to download the source of kdebase

Hi,man!
I want to see the source code of konqueror and some of softwares in CentOS，so i tried to down the SRPM,but i found that all in kdebase were patch files.
Where can i download the full source code.
By the way i had tried this:yumdownloader --source kdebase,but it could not find kdebase.
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