Detect a specific range of correlated variable

I have a matrix and it is 100 row by 16 column. I am trying to find the correlation coefficient of the 100 variable (row) and select the rows with 0.3 and -0.3 correlated variable, I used the code bellow :

         X=xlsread('data1.xls');
        [R,P]= corrcoef(X');

R is a symmetric matrix ( 100x100) , how can I specify the variable with 0.3 and -0.3 correlation. what i mean is if i have 100 row then when i select the rows by cutoff 0.3and -0.3 then the row will decrease to 50 for example