Some classes of explicit and exact travelling wave solutions of a nonlinear dispersive - disspative equation ， which describes weak nonlinear ion - acoustic waves in a plasma consisting of cold ions and warm electrons ， are obtained by a kind of com bination of the direct algebraic method and the ansatze method . some results of other papers can be regard as a special case . the method in this paper can also be applied to the higher dimensional nonlinear evolution equations 本文通过直接代数方法与假设方法的一种结合求出了一个用于描述由冷离子和热电子组成的等离子体弱非线性离子声波演化的非线性色散-耗散方程的几类显式精确行波解.这里的结果包含已有文献的结果作为特例.本文的方法也适用于高维非线性发展方程
