i have 44 percentage in b.com.now whether i m eligible for exam of not?

For CAT, NMAT you are not eligible because as per the criteria officially one needs 50% in graduation if general category and other reserved categories its 45%. So even if you belong to a reserved category you are not eligible.

Coming to other exams, XAT, CMAT, MAT are few exams which you can give as there is no minimum percentage requirement officially mentioned.

Let me tell you, XAT, CMAT, MAT are again in the list of top exams for MBA courses and colleges through it.
If you get the good percentile and crack the interview and impress the panel you can make the admissions in top bschools in India.
All the best.

Applicants should hold a Bachelor’s Degree with minimum 50 per cent marks or equivalent CGPA awarded by a recognised university & For the reserved category candidates, such as Scheduled Caste (SC), Scheduled Tribe (ST) and Persons with Disability (PWD), the minimum percentage to be secured in Bachelor’s Degree is 45 per cent. So you are not eligible for CAT but you can apply for other management exams like MAT, XAT, CMAT as there is no any restriction for minimum percentage eligibility to apply for the exam. For further information you can go through with given below link.

CAT Eligibility

Good Luck!