The phrase "a previous study revealed" is correct and usable in written English.
It can be used when referencing findings or conclusions from an earlier research study in academic or professional writing.
Example: "A previous study revealed that regular exercise can significantly improve mental health."
Alternatives: "an earlier study showed" or "a prior study indicated".
In addition, a previous study revealed that the presepsin level typically elevates earlier than PCT [14].
A previous study revealed that transient recurrent situational insomnia was associated with headache [11].
A previous study revealed that swollen hepatocytes and fibrosis were present in liver specimens of patients with PMM2-CDG [9].
A previous study revealed that the detection of hypoventilation by pulse oximetry is reliable only in room air breathing conditions [8].
A previous study revealed almost 700 endogenous peptides from 30 different proteins in human milk through extensive mass spectrometry analysis (Guerrero et al. 2014).
A previous study revealed that silica gel and synthetic opal showed no evidence of crystallization during thermal treatment up to 1000 °C (Arasuna et al. 2013).
Indeed, a previous study revealed an association between perception of poor sleep quality and worse cognitive performance in healthy elderly individuals [49].
A previous study revealed that water tainted by peat swamp leachate contained a higher quantity of trihalomethanes compared to water from non-peat water sources [1].
A previous study revealed that a major need for users with blindness is to quickly reach the information relevant to the task, by filtering redundant and irrelevant information.
A previous study revealed that CD11b+ myeloid cells adhered to the surface of tumor cells to induce tumor PD-L1 expression through the p38 pathway (Noh et al., 2015).
A previous study revealed that a furoclerodane derivative, e.g., croblongifolin, isolated from the stem bark of Croton oblongifolius (syn. Chrozophora oblongifolia) possessed significant cytotoxicity against various human tumor cell lines including HEP-G2, SW620, CHAGO, KATO3 and BT474 [33].
