"has been further shown" is a correct and usable phrase in written English.
You can use it when you want to emphasize that something has been shown to be true or accurate multiple times. For example, "The importance of proper nutrition for good physical health has been further shown in recent studies."
It has been further shown that all these results hold even if doglegging is allowed.
Based on the interpretation of computed tomography scans of a relatively uncrushed specimen, it has been further shown that its fin skeleton possesses the most tetrapod-like features of any fish (Boisvert et al. 2008; Figs. 1 and 6).
It has been further shown that this effect results from competition for resources between host and parasite [21].
In the same promoter region, a single nucleotide polymorphism (rs25531), implying an A to G substitution, has been further shown to alter the degree of gene expression [29].
It has been further shown that subjective workload is associated with job satisfaction, such that the lower the workload, the higher the job satisfaction.
It has been further shown that only 30% of patients received treatment at a health facility within 24 hours of onset of symptoms [ 23].
In some systems, the spike patterns have been further shown to adapt to local characteristics of the stimulus statistics, indicating efficient coding, e.g. [16], [18], [44], [45], [67] [71].
These mutations were previously shown not to be polymorphisms by sequencing control samples from various ethnic groups [28], [29] and had been further shown to be loss-of-expression and loss-of-function in other patients with MSMD [28], [29].
miRNAs have been further shown to regulate various physiological events relevant to DM pathophysiology, such as insulin biosynthesis, insulin secretion, insulin action, insulin responsiveness, and energy homeostasis.
Within such formulation it had been further shown that the classical Newtonian dynamics in physics, including Newton's renowned second law, may be regarded as one of its special cases.
Inverse associations between MEP and systolic and diastolic BP have been further shown in elderly adults from the Prospective Investigation of the Vasculature in Uppsala Seniors study (Olsén et al. 2012).
