The phrase "a combination of higher level" is correct and usable in written English.
It can be used when discussing elements or factors that are integrated or merged at a more advanced or sophisticated stage.
Example: "The project requires a combination of higher level thinking and practical skills to achieve success."
Alternatives: "a blend of advanced elements" or "an amalgamation of elevated aspects".
That, the researchers say, suggests that the vulnerability of particular tissues to Alzheimer's disease could, in part, be down to a combination of higher levels of plaque and tangle-forming proteins and problematic levels of proteins that affect their clumping.
A combination of high level variability of FadD22 across Mycobacteria with its conservation within taxonomic units indicates crucial importance of this protein for bacteria.
The Chinese Communist Party seems as secure as it has been at any time in its 55 years in power, delivering a combination of high levels of economic growth and considerable personal, if not political, freedom.
We created a software package and a user interface on top of a commercial data analysis package (matlab) by a combination of high-level and low-level programming.
We propose a uniform spatial data access middleware that can provide a combination of high-level, multi-modal, semantic, and quantitative-qualitative spatial data access and analytical capability.
This paper presents the first attempt to calculate ligand-binding free energies using a combination of high-level ab inito FMO methods together with PBSA techniques to derive reasonable estimations of enthalpy, entropy and solvation energies.
A combination of high-level political commitment, effective surveillance through systematic blood screening, and community involvement made the success possible.
In most circumstances, leaders included a combination of high-level executives, such as Chief Medical Officers, as well as physician leaders who were early adopters.
In the United Kingdom's introductions of the Hib and meningococcal C conjugate (MCC) polysaccharide vaccines, for example, this was achieved by a combination of high levels of immunization, high vaccine efficacy, and "catch-up" campaigns.
Thus, a personality characterized by a combination of high levels of neuroticism and low levels of extraversion could be seen as a vulnerability factor for developing anxiety disorders in adults [ 4] and youths [ 5, 6].
