The phrase "specializing exclusively" is correct and can be used in written English.
For example, you could use it in the sentence "He has been specializing exclusively in American art since he graduated from college."
Sparkling Pointe, in Southold, Long Island's only producer specializing exclusively in sparkling wine, kept its portfolio entirely brut — dry — starting with its first vintage in 2004.
Others like Cerner Corp. in Kansas City, Mo., are specializing exclusively in health IT along with upstarts like Athenahealth Inc. in Watertown, Mass.
Accordingly, we can predict that cuckoos specializing exclusively on chaffinches will show a broader range of hues than cuckoos specializing exclusively on bramblings (provided these chaffinches have the same egg discrimination skills and range of clutch colors as Fennoscandian chaffinches).
I specialize exclusively in Chapter 7 Bankruptcy & Chapter 13 Bankruptcy in MN.
The Oakes Ames Orchid Library AMESspecializeszexclusivelyely on the identification and classification of the orchid family or Orchidaceae.
Oil and gas companies are some of the largest companies in the world, and many financial traders specialize exclusively on oil and gas.
If you're worried about hair loss, it is important to consult with a both your primary doctor and an experienced hair restoration physician -- someone who specializes exclusively in the medical diagnosis, treatment and tracking of hair loss and its treatment.
Derived lineages, which have specialized exclusively in water-surface locomotion through rowing (all Gerridae and some Veliidae), have long legs compared with their basally branching relatives, but they also evolved longer mid-legs relative to rear-legs.
Mere paces away, an artfully bearded fashion victim wearing an ostentatious hat smoked a cigar while sitting in the gutter across from Urth Caffé, a local chain that specializes in "exclusively organic coffees" and $13 salads.
The proximal mesodermal cell masses turned out to specialize almost exclusively into blood cells.
By contrast, a second strain appears to specialize almost exclusively on roe deer.
