The phrase "a long substantial" is not correct as it lacks a noun to complete the thought.
It could be used in contexts where you are describing something that is both lengthy and significant, but it needs to be followed by a noun.
Example: "The report provided a long substantial analysis of the issue at hand."
Alternatives: "a lengthy significant" or "an extensive meaningful".
But he had a long and substantial career in letters of the sort that was far more prevalent a half-century ago than it is today.
Despite a long and substantial exposure to supermarkets (in most cases 20 years or more) there was still little indication that consumers were moving towards or planning to move towards buying their fresh foods in supermarkets.
(San Diego officials have made a concerted effort to expand the sources of their water over the years — including a long-contested, substantial transfer of Colorado River water from inland farmers — so they are not as reliant on the district as they once were).
For a long time a substantial minority has sought full independence from Denmark, and in 1999 the Landsstyre entered negotiations with the Danish government about conditions for full independence.
During the day L'Oasi functions as a takeaway bottle-shop, but from 5.30pm staff begin piling up a long table of substantial nibbles to accompany the aperitivi of homeward-bound students and workers; at €10 for a glass of wine or beer and a plate of goodies, this buffet – available until 8.30pm – is an excellent way to dine cheaply.
But King told Chalkbeat that integration "has a long history and substantial evidence" of success.
These attacks are a distortion of her record as a United States Ambassador and they ignore a long list of substantial accomplishments.
BUCKy-pop strictly runs in serial, using a Bayesian Markov Chain Monte Carlo (MCMC) technique, which can take a long time and substantial memory to reach convergence.
National cancer registration in England provides reliable population-based incidence data over a long period, with substantial numbers even for rare cancers (Quinn et al, 2001).
The first point is very important and the same 'prion hypothesis' is a good example of this, as it was under attack for a long time until substantial evidence was produced in its favour.
