Interval oscillation criteria for second order nonlinear delay differential equations

New oscillation criteria established in this paper for the second order nonlinear equations (r(t)psi(x(t))x'(t))' + F(t, x(t), x'(t), x(tau(t)), x'(tau(t))) = 0 are different from most known ones in the sense that they are based on the information only on a sequence of subintervals of [t(0), infinity) rather than on the whole half-line. Our results are more general and sharper than some previous results and handle the cases which are not covered by known results. Several examples that show the generality of our results are also included.