The crusades were numerous and spread out over a long span of time. But given the nature of your question Im gonna assume this to mean crusades into the Islamic heartland, as those in the 1300-1400s were primarily against the Ottomans.

Ok, so 'were the crusades partly responsible for the decline of Islamic sciences?'. The rise of scientific achievement in the Islamic world was no simple, straightforward matter, but rather the product of several dynamics that coalesced over a period of time. Likewise, the fall of that society and the deterioration of its scientific capabilities too was a complex matter with many points of consideration, and it didn't happen over night. So that being said, did the crusades have an affect at all on the decline? Just by nature of how long the crusades took place and their scale/practical implications Im sure at some level there is a degree of 'impact'. But this is no different from the fact that in-fighting between Islamic powers themselves also had a major impact on the decline of Islamic sciences. My pedantic point being, there had to be some degree of 'effect', given these events are all a part of the bigger picture.

But I would stop far short of saying this was the greatest or even a major reason for the decline of Islamic sciences. The Muslim world at the time of the crusades was already rather fragmented and antagonistic to each other. Many different factions were already warring, and with that being the narrative, the Latin Crusaders would have just been another warring faction in the mix-albeit non Muslims. All things considered, you could even argue that the Crusades had a larger geo-political impact on Europe than the Middle East. True, the crusades were violent and disruptive. But when we are talking violence and destruction, nothing wrought more havoc on that region than the Mongol invasions. No two ways about it. I know you asked about the crusades, but just for arguments sake I'm gonna shift the question to after that catastrophe. Technically, it still falls within the bounds of your question.

So were there any major contributions from Islamic scholars after the crusades? (and Mongol invasion). Yes!. In fact, two of the greatest Islamic scholars of all time lived after this period.

First we have al-Tusi. Tusi was a polymath whose expertise spanned basically all the natural sciences. But where he shines the most is astronomy. He had Hulagu Khan, the one who executed Baghdad, build him an observatory. He then went on to create the Tusi Couple, a mathematical model for relating linear movement from circular motions, which he used to create one of if not the most accurate table of planetary movement of his time- greatly aided by having access to the best observatory of the day. This technique and knowledge would then, several centuries later, be used one Copernicus in developing his own astronomical theories. Tusi was also the first to posit that the milky way was in fact just tight clusters of stars. This would be confirmed later by Galileo.

Another notable remark, Tusi put forward a very early version of the theory of Evolution. From the link, "The organisms that can gain the new features faster are more variable. As a result, they gain advantages over other creatures. [...] The bodies are changing as a result of the internal and external interactions." Definitely look into him as his accomplishments and acumen go far beyond simply these 2 things.

Next, we have Ibn Khaldun who lived a century after Tusi. This is our guy for this subreddit :)

Khaldun wasa prolific philosopher and historiographer, a pioneer of modern sociology, historiography, and economics. Khaldun's works and musings cannot be divorced from any of these subjects even in modern day. He was a paramount figure in all of these fields, and I could honestly go one about it all day.

However, I will wrap up by sharing a major theorem that Khaldun grappled with in his lifetime, which as a devoted student of history I find just so fascinating. Khaldun posited that all societies in the history of humanity have followed the same general progression. Nomadic peoples discover a sustainable lifestyle and thus they create a great society. The pleasantries and refined lifestyle of this new civilized existence lulls the society into a state of complacence and reluctance. The peak is always followed by decay. And sometimes thereafter, the softness of this civilization is taken advantage of by 'lesser folk' who in comparison are Barbarians. The barbarians then adopt and adapt the refined ways of the culture they conquer, and then they too become 'soft'. Only to be seized once again by another group of Barbarians. And thus, the cycle repeats. Interesting stuff.

The destruction of the House of Wisdom, an institution that could be considered the first university, during the siege Baghdad in 1258 by the Mongols is probably a much more significant event than the crusades.

Baghdad was the main center of Islamic learning, and it was never touched by the crusaders. But it was sacked two times by the mongols, first in 1258 and then in 1401 by Tamerlane, when it was almost razed. After that the islamic golden age was truly finished.