How to fix import error 'nvcuda.dll' in spyder for python?
As the comment mentioned, you need to ensure the time you import the tensorflow, the path environment points to c:\windows\system32 and as you said you have nvcuda.dll, ensure the file is there too. There is no need to set the libraries.
1.I already have nvcuda.dll in system32.
2.I have path C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v9.2\bin.
3.The program already upgraded tensorflow and GPU tensorflow.
I check import still have the error. 

ImportError: Could not find 'nvcuda.dll'. TensorFlow requires that
  this DLL be installed in a directory that is named in your %PATH%
  environment variable. Typically it is installed in
  'C:\Windows\System32'. If it is not present, ensure that you have a
  CUDA-capable GPU with the correct driver installed.

Why?
How to fix this problem shown by the message error ?