It looks like you need to flush stdout periodically (e.g. sys.stdout.flush()). In my testing Python doesn't automatically do this even with print until the program exits.
You can run Python with the -u flag to avoid output buffering

nohup python -u Bilstm-My-Exp-Char.py --training 1 --char_base 1 --window 5 --rnn_active relu --data_root ../../wangzhen/bilstm/ --load_embed 1 --model_pkl mdl5-15-14-30 > 5.txt 2>&1 &