"long been emphasized" is correct and usable in written English.
You can use it whenever you need to emphasize that something has existed or been true for a long time. For example: "The importance of a good education has long been emphasized."
The links between them have long been emphasized by scholars like Frank Partnoy, who published a detailed law review article on the topic in 1999.
The relevance of one's self-concept as a reader has long been emphasized in reading research.
Inference has long been emphasized in the comprehension of verbal and visual narratives.
The importance of WOM has long been emphasized by marketing researchers and practitioners for a number of reasons.
Finally, interest of ultrafiltration has long been emphasized in these patients, but review of its use is out of the scope of this manuscript.
And while Bush might not like to admit it, the truth is that Ziedrich's comments capture a point that has long been emphasized by Middle East watchers -- namely, that the Bush administration's mismanagement of Iraq encouraged thousands of skilled Iraqis to take their expertise to the anti-American insurgency that eventually became the Islamic State.
The focus on emerging markets is one that WPP's CEO Martin Sorrell has long been emphasizing.
For the Coleoptera, its flight has been emphasized for long.
In previous studies [ 8– 10], the importance of maintaining appropriate PI-LL has been emphasized, particularly for long-segment fusion for adult spinal deformity; however, there are few studies evaluating the influence of PI-LL on surgical outcomes following short-segment fusion.
The role of super-spreaders has been emphasized in the epidemiological and physics literature since a long time.
Whichever way (or ways) you think that relationship works, it appears that both Washington and news organizations have been emphasizing long-term debt reduction over near-term job growth.
