The phrase "a string of regimes" is correct and usable in written English.
It can be used to describe a series of governments or political systems that have succeeded one another, often implying instability or a lack of continuity.
Example: "The country has experienced a string of regimes, each one more authoritarian than the last."
Alternatives: "a series of regimes" or "a succession of regimes".
A string of regime-organised sectarian massacres in 2012 irretrievably hardened the mood.
The concerns about personal safety for Assad and his staff also have been reinforced by a string of attacks targeting top regime officials.
The infighting has taken a heavy toll on the fight against Assad, leaving the rebels battling on two fronts and enabling a string of steady gains by the regime forces around Aleppo.
After a string of court defeats, the government was forced to expand access to the medical marijuana regime.
He helped the rise of the Houthis, who practise a Zaydi version of Shia Islam that is largely unique to northern Yemen, though his regime fought a string of bruising wars with them between 2004 and 2010.
Although Japan had accused North Korea of committing a string of such kidnappings, Kim Jong Il's regime did not admit to it until 2002, when Junichiro Koizumi, Japan's prime minister, made a trip to Pyongyang.
Critical of the Bush administration's foreign policy, Roh sought to improve ties with North Korea, and in 2007 signed a string of economic agreements with the secretive regime's leader, Kim Jong-il, at a rare inter-Korean summit in Pyongyang.
Judge Nunez is one of a string of puppets controlled by the ruling regime".
He unwittingly helped the rise of the Houthis, who practise a Zaydi version of Shia Islam that is largely unique to northern Yemen, though his regime previously fought a string of bruising wars with them.
Most recently they have forced the regime to abandon a string of checkpoints in and around Marat Numan, a town in Idleb province that straddles the main Damascus-Aleppo road.
