you should study from dpharma books as per pci syllabus.
For practice use ESIC pharmacist previous papers. You can also practice from previous gate and GPAT papers , but only diploma level questions.
You can download syllabus of CGHS and marks distribution from here
DOWNLOAD CGHS PHARMACIST SYLLABUS
you can download ESIC pharmacist previous papers and gpat papers from here
PHARMAGANG DOWNLOAD SECTION