"broad sphere" is a correct and usable phrase in written English.
It can be used to refer to a wide range of subjects, activities, or interests. For example, "He has a broad sphere of knowledge on a variety of topics."
Because they maintain positions in multiple boards they are central in the interlocking directorate network and have broad "spheres of influence" (Levine 1972; Windolf 2002) that include not only business companies but often extend into the non-business environment.
Today, birdwatching encompasses broad spheres of societies in several developed countries, particularly in the USA and the UK.
Current knowledge indicates that the reasons for the poorer health of people with intellectual disability primarily fall within two broad spheres.
In a broader sphere of what could be called "personal development" the most valuable language for me has been Hungarian.
The Russian economy has been stung by Western sanctions and lower prices for its chief exports — oil and gas — testing Moscow's ability to shape a broader sphere of financial influence.
The term "street harassment" is relatively recent, and helps describe a broader sphere of violence that limits participation in public space (see Sidewalks, by Anastasia Loukaitou-Sideris and Renia Ehrenfeuch).
He cited Monument Valley, a handsome iPhone game, released in 2014, that plays with M. C. Escher-esque tricks of perspective, as an example of a game that has been hugely influential in terms of color, shape, geometric pattern, and typography in the broader sphere of graphic design.
At its basic level, leadership is developing the capacity to transform our own lives and circumstances, and as our confidence grows we extend that capacity to our broader sphere of influence.
A stalwart supporter of the Royal College of Surgeons, he wanted to maintain gynecology within the broader sphere of surgery, and he was determined that radiotherapy should remain the handmaiden of surgery.
