"extensively demonstrated" is correct and usable in written English.
You can use it to describe something that has been experimentally studied or proven with data. For example, "The benefits of this new type of vaccine have been extensively demonstrated in clinical trials."
This has been extensively demonstrated.
The efficiency of these Iterative Learning Control ILCC) algorithms is extensively demonstrated in this paper.
The ratio of salt to hypertension, cardiovascular and cerebrovascular diseases has been extensively demonstrated in several studies.
The efficacy of plant-produced CVPs in inducing antibody responses specific to the displayed peptide has been extensively demonstrated.
The potential of reset controllers to improve the transient performance of linear (motion) systems has been extensively demonstrated in the literature.
The usefulness of these descriptors in QSAR studies has been extensively demonstrated, and they have also been used as a measure of structural similarity or diversity.
Nevertheless, further studies are needed to demonstrate its validity in different clinical situations as it has been extensively demonstrated with the original tool.
In ICUs, noise levels have been extensively demonstrated to be above the World Health Organization recommendations [20, 21].
The usefulness of these descriptors in QSAR studies has been extensively demonstrated, and they have also been used as a measure of structural similarity or diversity [45, 47].
The viral delivery of CRISPR components has been extensively demonstrated using lentivirus and retrovirus (Shalem et al., 2014; Williams et al., 2016).
The critical influence of HS on the physical, chemical, and biological properties of soil has been extensively demonstrated and their role in sustaining plant growth recognized.
