I, Konoha's Sage of Life - Chapter 397: Sensei… Take Me With You!

In Zhenhai City, the Chu Family receives an imperial decree that revives the hope of reclaiming their ancestral title, but only if a descendant places in the top three of the Martial Examination. For young Chu Yangxiang, who unexpectedly discovers he has Grade 1 Martial Dao Talent, this honor seems within reach. Yet, as he rises, envy and family rivalries emerge, with the privileged Chu Xiaoxiang demanding loyalty—or threatening to ruin him. Determined and battered, Chu Yangxiang faces a brutal choice: submit or fight for his family’s legacy. Will he overcome these powerful?

A scientific genius named Thomas Harrier was transmigrated to an imperial prince body after a car accident that took his life. He found out that he is in a world similar to our own with a timeline akin to early twentieth century. The body that he is occupying was the imperial prince of a failing empire who suddenly rose to power after a successful assassination attempt of his father. Unaware that the attack is just the beginning of what is to come. He faces many challenges throughout. Will Thomas Harrier be able to live his second life in peace while running an empire and getting it back to its former glory? Or will he succumb into a conspiracy lurking within the country's borders?

Expect some:

Cold war era techs.

Super battleship with advanced electronics, propulsion, and fire control systems?
Helicopters?
Missiles?
Modern medicines and equipment?
AC-130?
A nuke?
Challenger or Abrams or Leopard?
F-4 Phantom or MIG-21?
Colored TV's.

Everything!!!

PS. Cover not mine, I just found it on google.

In the Toaru Kagaku no Choudenjihou (Railgun) SS series:

Set in Liberal Arts City between September 3rd to 10th, Academy City is having an exchange program with the rest of the world that allows some students to travel for this week to other places, and some students are allowed into Academy City during this time.

V.2 – Shopping Mall Demonstration

Setin Russia where Misaka Mikoto takes part in a demonstration things don’t pan as scheduled as Mikoto meets the mysterious New Light.

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The story was released in parts on limited edition DVDs and Blu-rays of the Toaru Majutsu no Index anime. The story consists of eight parts, and can easily equate to a regular Index novel in length.

In the foreign world, the martial artists dominate the world and the sword of the emperor controls the fate of hundreds of millions of lives! Long Yu, the number one killer on Earth, after dying, takes rebirth in this new world in an aristocratic family of martial artists but faces rejection because he is unable to practice martial arts.

- Description from Novelupdates