There are all kinds of pdf books, including but not limited to teaching materials, and many small practical documents. Most of the downloaded links are web disks. Generally, e-books are not big, so speed is not a problem.
2. Network disk search is also a very practical function, including Baidu network disk, Sina network disk and so on.
3. National Library Reference Union
This is a rather laborious method. The book kk found in it was maliciously delivered through the library, but only 50 pages can be delivered at a time, so it is still very troublesome to get a whole book.
Step 4 buy treasures
There are also many book search services on a treasure, and the prices are mostly in the range of 3-5 yuan, with more or less. If it's simple and fast, and it's not bad money at the same time, then you can choose this one.
5. WeChat search
There are many articles on WeChat now, and the official account of WeChat has also published related books, so you can try your luck.
6. Higher education bookstores/e-books/
This is a special electronic teaching material, which can be found in middle schools, high schools, universities and teachers. For example, if you want to find electronic textbooks for universities, you can click on higher education, and then you can see electronic textbooks for various disciplines of universities, including philosophy, economic management, law, news communication, mathematics and the universe, chemistry, chemical engineering and pharmacy, biotechnology, computers, agriculture, forestry, medicine, mechanical energy and other related electronic textbooks.