In this paper, we afford some sufficient conditions 

to guarantee the existence of positive solutions 

for the nonlinear boundary value problem

$$\left\{\eqalign{

&(E)\quad \bigl(\phi(u')\bigr)'+ f(t,u)=0,\qquad 0<t<1,\cr

&(BC)\left\{\eqalign{

& u(0)-B_0\bigl(u'(0)\bigr)=0, \cr

& u(1)+B_1\bigl(u'(1)\bigr)=0.\cr

} \right. \cr

}\right.\leqno (BVP)$$