The phrase "a unique investigation" is correct and usable in written English.
You can use it when referring to a specific investigation that is distinct or one-of-a-kind in nature or approach.
Example: "The researchers conducted a unique investigation into the effects of climate change on local wildlife."
Alternatives: "an original inquiry" or "a distinctive study".
Also, a unique investigation involving studying local oxidative stress of infected paw skins as an indicator of fungal infection was performed.
"It was a unique investigation to be involved in, as the perpetrator had been identified long ago and brought to justice while the victim's identity remained unknown.
The Nevinsons were only keeping a diary because of a unique investigation launched by Benjamin Seebohm Rowntree, who ran the family chocolate company.
"This is a unique investigation in the history of our organization.
The last spacecraft to visit Jupiter was New Horizons in 2007, which carried out a unique investigation of the Jovian magnetotail, traveling as far as 2500 RJ along its length.
In summary, this pilot study provides a unique investigation of the functional effects and molecular mechanisms of somatic mutations attributed to tumorigenesis and anticancer drug responses.
DI Jon Fanner, of Sussex police, said it had been a "long, complex and unique investigation".
Led by Sarosh Kuruvilla and co-authors, this is a unique empirical investigation of audit data from over 3,000 audits in six industries across 30 countries.
Most importantly, we summarize the procedures that have been designed to allow UVCS/SOHO data to be used by a wide array of researchers, and invite participation in this unique investigation.
Reece Shearsmith and Steve Pemberton return with a brand new Inside No.9, telling the tale of the demonic Krampus, whilst Philomena Cunk brings viewers her own unique investigation into the real meaning of yuletide's traditions, in Cunk On Christmas.
A number of theoretical [6] [8] and empirical [9], [10] studies have investigated patterns of metapopulation synchrony in larger habitats with local movement and, importantly, where abundance fluctuations are under deterministic control (limit cycles, chaos) but this unique investigation explores the dynamics of noise-driven, small metacommunities.
