how to translate? "the ability to access the full spectrum of available English research materials“， Please translate this sentence to Chinese. Thanks.

How to improve Oral English? I have been learning English for almost ten years, and I am also major in English in university. However, my spoken English is not good. Sometimes I am very nervous when I speak English in Public. I need to practice my spoken English and if you have any questions in learning Chinese, feel free to ask me. What's more, are there any methods to improve oral English? Thank you in advance.