The phrase "a particularly firm" is correct and usable in written English.
It can be used to describe something that is notably strong or solid in a specific context, such as texture, opinion, or stance.
Example: "The mattress is a particularly firm option for those who prefer extra support while sleeping."
Alternatives: "an especially strong" or "a notably solid".
They just sat down and chatted, which isn't a particularly firm foundation for a psychological system.
It was a year when five teams held the No. 1 ranking, none with a particularly firm grip.
With its penchant for extreme close-ups, the show finds its ideal subject in Passard, a man prone to lurching excitedly towards the viewer as he describes the beauty of a carrot or the wit of a particularly firm beetroot.
She doesn't have a particularly firm grasp of the future either, as she spent the first three months of this year telling us that Ed Miliband would be prime minister.
The sentence was just short of what prosecutors had sought, tougher than those for previous Illinois governors convicted of crimes, and was widely viewed as a particularly firm punishment intended to send a loud, memorable signal in a state that has been plagued with political corruption for decades.
"While this is a positive step, we don't see it as a particularly firm base for someone to be regularly faced with prospect of eviction.
One savvy outfit from Chicago does not even use the words "private equity" in Asia, instead describing itself as an "engineering firm"—a particularly appealing label for emerging-market companies, which typically seek expertise and technology as much as money.A second limit on the private-equity recovery is the cockroach-like survival of the region's big and inefficient conglomerates.
One strategy for answering this question, which centers on non-epistemic forms of necessity, starts from a certain conception of what (non-epistemic) necessity consists in: for a proposition to be necessary is for its truth to be, in a certain sense, particularly firm, secure, inexorable or unshakable in a wholly objective way.
Nor was it a particularly British firm.
Reformers should be "careful what they wish for" says Rod Christie-Miller of Schillings, a particularly ferocious firm of London libel lawyers: "The more laws you make, the more money lawyers make".
Tradition seems particularly firm on this point.
