"years effort" is correct and usable in written English.
You can use it when referring to the amount of time and effort that has been invested into something over a period of years. For example, "It has taken years of effort to make this project a success."
Deep Blue is the culmination of several years' effort to program computers to play chess.
In recent years, effort has been made to make the results of fluid inclusion studies applicable and use them in the design of the exploration process.
Reflecting on the litigation, Mr. vanden Heuvel said the dispute was "painful," especially "when we're about to celebrate an extraordinary triumph of 40 years' effort".
In Under the Eye of the Clock (1987) he described his own life; another 10 years' effort brought a substantial saga, The Banyan Tree (1999), drawing on some of his family's history as small-time farmers.
They don't like the once-in-a-lifetime tidying marathon, which on average is completed in six months; sometimes organizing is a many years effort or an ongoing one.
Reflecting on the litigation, Mr. vanden Heuvel said the dispute was "painful," especially "when we're about to celebrate an extraordinary triumph of 40 years' effort". But he said that the park would abide by the court's decision.
FEM programs are developed through many years' efforts.
In recent years, efforts have been made to use pultruded FRP PFRPP) materials in the construction industry.
In the recent years, efforts are made to extend the SVM algorithm to support multiple classifications.
2003 "For 20 years, efforts to reform the schools were stymied by politics as usual.
Over the years, efforts to redevelop the old market, called Mart 125, have failed.
