I assume you want to buy bonds in fresh issue and not already listed bonds
What exactly you want to search for? bonds available for buying, yield etc?
This information is also available in Coin when issue is open
https://coin.zerodha.com/dashboard/gsec/invest
Bhuvan maintains a list of Issuance calendar for GOI security which can give you idea of when issue would be open
If you still want more information you can look at RBI’s press releases here:
https://www.rbi.org.in/Scripts/BS_PressReleaseDisplay.aspx?prid=54459
Hope this gives you starting point.