Bisbenzylisoquinoline alkaloids from roots of Thalictrum atriplex Synergistic Interaction Between Ys-96,A Bisbenzylisoquinoline Compound Derived from Stephania tetrandra,and Adriamycin or Vincristine Against Human Cancer Cell Lines in Vitro Reversal Effect of Ys-96, a Bisbenzylisoquinoline, on Adriamycin or Vincristine Resistance in Human Cancer Cells in Vitro