The phrase "a number of modalities" is correct and usable in written English.
It can be used when referring to various methods, forms, or approaches in a particular context, such as in research, therapy, or communication.
Example: "The study explored a number of modalities for delivering educational content to students."
Alternatives: "several methods" or "various approaches".
There exist a number of modalities and expressions that could be used for affect recognition.
There are a number of modalities available to treat this condition, of which corticosteroid injection is, perhaps, the most popular.
A number of modalities have been described to delay the growth of one limb to allow growth in the contralateral limb and correct the overall leg-length discrepancy [6, 7, 8].
Three-dimensional medical imaging from a number of modalities, including magnetic resonance (MR), computed tomography (CT), and positron emission tomography (PET) is in common use in contemporary clinical practice.
A number of modalities exist that enable localized prostate ablation.
A number of modalities and methods have been explored to quantify glenoid bone loss.
MR imaging is the modality of choice for follow-up of the surgical field, however, a number of other modalities can be useful in specific instances to confirm or exclude tumour recurrence.
It is much better for the environment -- it is much more cool, you know -- to rely on a number of transportation modalities: the bus, the train, a fleet of shared cars".
A number of bioprinting modalities have been explored, including inkjet printing, extrusion-based technologies, and laser-induced forward transfer.
It has a number of imaging modalities in its armamentarium which have differing physical principles of varying complexity.
A number of imaging modalities for small animals evolved over the last decade and were successfully applied in numerous studies [8].
