This is the 5156th most frequent Russian word.
научно
Scientifically.
In this sentence, 'научно' functions as an adverb, emphasizing that the proof or reasoning is based on scientific methods and knowledge.
Научно доказано, что физические упражнения полезны для здоровья.
It is scientifically proven that physical exercises are beneficial for health.
Here, 'научно' modifies 'сложным', specifying that the complexity is related to scientific aspects.
Мы работаем над научно сложным проектом.
We are working on a scientifically complex project.
In this example, 'научно' is part of the compound adjective 'научно-технических', describing the type of research as related to science and technology.