From Conflict of Nations Wiki
- Your country’s doctrine is essential to what research is available to you at the start of the game.
- New research is unlocked almost everyday, and is hierarchical in its progression. This means that you cannot research higher level technologies unless you have unlocked lower tier prerequisites.
- Ongoing research can be cancelled at any time and you will be refunded proportionally to how much research was completed before the cancellation.
If you are researching an upgrade for an existing unit, you can click the 'i' button to see the unit-specific stats, allowing you to take note and compare how other units might fare.
Your nation's doctrine is key to what research you will likely prioritize during the game. The image below gives you a visual guide to the units which are available first for research per type and doctrine.