The base duration of a research action varies depending on the research type.
The research time can also be modified in various ways. The most notable one is upgrading your reduced research time stat, which will affect every action in the Research menu with the exception of Scientists travelling to and from planets. Other ways include paying Diamonds or watching ads to instantly complete one research action or completing Daily Quests and collecting Red Bacteria to reduce the remaining time for all active research actions.
Reduced Research Time
Reduced research time (RRT) is a bonus that can be obtained from Evolved Bacteria or Dark Matter Institute. It decreases the time that it takes to complete all activities in the Research Labs with the exception of sending and recalling Scientists in the Planetary Research section.
If you have already started a research, then changes to your RRT will no longer affect it.
The RRT bonuses from different Evolved Bacteria are not additive. Instead, each Evolved Bacteria with the bonus reduces the research time remaining instead of the original research time. 
For example, if the player has three Evolved Bacteria equipped with RRT of 13.3%, 12.1%, 13.8%, then the total RRT would be 34.3% not 39.2%. 
This means that it's practically impossible to reach 100% RRT.
The RRT displayed in the Bacteria Evolution menu does not include reductions to research time from Dark Matter Institute.
Main page: Reduced Research Time
Research ads reduce the remaining research time of a selected action by 1 hour.
Up to two ads can be watched before an 8 hour cooldown becomes active. To view the option to watch the ad, press and hold on an active research action.
Main page: Rewarded Ads
Main page: Red Bacteria
There's a random chance that a Tier 3 or Tier 4 daily quest will give some reduction to active research time (5% reduction for completing a Tier 3 quest and 15% for completing Tier 4).
The reduction is applied at the moment you collect the reward.
Main page: Daily Quests
Dark Matter Institute
Main page: Dark Matter Institute
The cost for instantly completing nanobot production is calculated differently from other actions, but it also depends on the amount of remaining research time.
|1.8.0||Added Alter Intellect - a Dark Matter upgrade that reduces active research time|