The phrase "a relatively narrow portion" is correct and usable in written English.
It can be used to describe a specific segment or part that is not wide in comparison to other segments.
Example: "The study focused on a relatively narrow portion of the population, specifically those aged 18 to 25."
Alternatives: "a somewhat limited section" or "a fairly small segment".
In the recent literature, most work to date has been focused in a relatively narrow portion of the expected range of tar materials, which has yielded a bias toward samples of relatively low viscosity and density.
Finally, the data used in this study came only from Nova Scotia, a relatively narrow portion of the range associated with many of the species.
Most species live within a relatively narrow portion of the world's available climatic breadth.
The second tends to be deeper and to occur in a relatively narrow portion of the inferior disc labelled macular vulnerability zone (MVZ) in figure 2F.
This suggests that although some light is absorbed by the gold coatings, this phenomenon is negligible compared to the fluorescence cell-to-cell variability, despite sorting transfected fibroblasts to retain a relatively narrow portion of cells expressing the transfected probe.
They are fairly robust against suppression of some relatively narrow portions of the spectrum.
Encyclopædia Britannica, Inc. Tundra vegetation, made up of lichens and mosses, occupies a relatively narrow zone in Iceland and the extreme northern portions of Russia and Scandinavia, although that zone is continued southward in the mountains of Norway.
Tundra vegetation, made up of lichens and mosses, occupies a relatively narrow zone in Iceland and the extreme northern portions of Russia and Scandinavia, although that zone is continued southward in the mountains of Norway.
Moreover, judging from the preserved ventral outline impression and changes in the orientation of the haemal spines (Figure 6B), the distal tail blade was hinged upon a relatively narrow caudal peduncle, and thus offset from the anterior, somewhat deeper portion of the tail (Figure 8).
Although the HA solution was made using HA powder, still a relatively narrow peak was observed in the SEC chromatogram of the acid soluble portion of the HA solution (data not shown).
Interestingly, the variable genome in Bm encompassed a larger portion of the genome (33 41%) than in Bp (20.6%), suggesting that even with a relatively narrow genetic base, the genome of Bm is continuing to change, albeit without actual gain of genes to the pan-genome.
