The phrase "a major difficulty to" is correct and usable in written English.
It can be used when discussing a significant challenge or obstacle that affects someone or something.
Example: "The lack of funding presents a major difficulty to the success of the project."
Alternatives: "a significant challenge for" or "a considerable obstacle to".
The French prime minister, François Fillon, told members of the governing party this week that "we are stuck with a major difficulty — to convince Germany that we should arm the euro zone with an instrument of defense for our currency with a certain evolution of the role of the central bank".
It is a major difficulty to produce the 1 13 phase because of its low phase stability at elevated temperatures and low atomic diffusivity [11,12].
Still, lack of substantial fossil evidence of the development of the wing joints and muscles poses a major difficulty to the theory, as does the seemingly spontaneous development of articulation and venation, and it has been largely rejected by experts in the field.
A major difficulty to distinguish between all these mechanisms is the lack of molecular tools to selectively block the formation of nanotubes, exosomes or microvilli.
A major difficulty to identify efficient treatments against TPs is the absence of models easily usable in laboratory.
A major difficulty is to avoid under-segmentation in the input segmentation, since under-segmented cells cannot be resolved into several cells by our approach.
A major difficulty is to accurately estimate the exposure level--the number of inhaled anthrax spores--of each individual in the exposed region.
A major difficulty is access to information and access to resources to help them get into educational institutions".
But even if these presuppositions are granted, the naturalistic project of looking to science for methodological guidance within philosophy faces a major difficulty, namely how to 'read off' from actual scientific practice what the underlying methodological principles are supposed to be.
A major difficulty is how to accurately validate the results of PET imaging because it is not possible to biopsy all abnormal sites identified.
A major difficulty turned out to be the securing of constant speed in both the recorder and reproducer.
