The phrase "and mainly the same" is correct and usable in written English.
It can be used to indicate that something is primarily similar to something else, often in a comparative context.
Example: "The two reports are quite different in their conclusions, but the methodology used is and mainly the same."
Alternatives: "largely similar" or "primarily alike".
The justices have the same powers the law lords enjoyed (they cannot, unlike America's supreme-court judges, strike down primary legislation), and are mainly the same people.
But the first recent coverage to get attention came from a little-known YouTube user, DaPhoneyRapperz, who uploaded a video supposedly showing the Democratic nominee convulsing and having seizures – mainly the same few bits of video of Clinton laughing or making faces looped to a creepy soundtrack – on 21 July and has more than 2.2m views.
If you search Quizilla a bit and take some quizzes with the same name, you will see that the questions and answers are mainly the same.
The doses of DBP used in these conflicting studies covered a similar range and mainly utilized the same route of administration (gavage).
The various architectures differ only in the bay level, with the process level, communication network, and SCADA level, having mainly the same properties in all architectures.
Extensive analyses with ScTWends in three categories (cut-off at 2.5 and 5.0 h) and as a continuous variable showed mainly the same pattern of negative β values for boys and positive β values for girls, although not statistically significant (data not shown).
Table 5 also shows that after controlling for the other score the pattern of relationships between the RA or PA scores and variables of interest were mainly the same as reported for the total sample, with a few notable exceptions being described next.
The resources and clinical approach to treat patients with PD are mainly the same in private and public primary care centres but in order to guard us for minor differences both sorts of centres were chosen.
Before writing or reading any text on history or related with history, it should be known clearly that past and history are not referring to mainly the same thing.
The photographic method in this age group is also in many ways comparable to the other methods, identifying mainly the same patients and showing comparable or only slightly inferior association with symptoms.
