Baidu, it is not good to give a link directly. You can go directly to Baidu People's Education Publishing House, or you can enter it directly according to the address of my picture below.
After entering official website, move the cursor to "Teaching and Learning Service" and click on the grade and subject you want to study.
Go to the teacher center below and you can see the "electronic teaching materials". After clicking in, you can see the textbooks of all grades. Click on the textbook you want to read, and you can view the contents of each page page by page. Internet explorer is recommended. Other browsers may not see the Next button.