"further underscore" is a correct and usable phrase in written English.
It is used to emphasize an idea or point. For example: "The data from the study further underscore the need for parents to provide their children with proper nutrition."
Pence used his trip to the region to further underscore the administration's combative stance.
The numerous candles, lanterns, and other sources of artificial light are characteristic and further underscore the indebtedness to Caravaggio.
The simulations provide a plausible description of the observed phenomenology and further underscore the unstable nature of nanocrystalline grain size distributions.
The proposals also further underscore the vast distance between Mr. Pataki, a Republican, and the national Republican Party on gun controls.
"To further underscore the homecoming theme for 'A Family Album: Brooklyn Collects,' " reads a museum news release, "the museum is creating 'Home Team,' a national membership campaign.
It was as if the sheer display of iron-pantsed discussion would further underscore her insistent theme: the hollowness of Obama's charisma.
The disparities observed in microbial abundance and diversity further underscore the immense value of state-of-the art molecular assays in augmenting traditional culture-based techniques.
Stratigraphic data and a recently determined radiometric date on basal Kessyusa volcanic breccias further underscore the significance of the Olenek region in investigations of the Proterozoic-Cambrian boundary.
One day won't make a difference, but the political spectacle and the final result only served to further underscore the president's weakness.
He will spend the remainder of the week giving repackaged versions of his address, looking to capitalize on the moment and further underscore his priorities.
To further underscore the advantage for CBS, the company's stock price shot up 6 percent in the first two days after the settlement.
