From a Chinese language interface resource is available a large amount of open access resources from the National Library of China.
My Chinese colleague has summarised its content as including:
1. PhD dissertations from China (free view of the first 24 pages of over 100,000 PhD dissertations);
2. Biographies of Sinologists outside China (over 150);
3. Chinese e-books (free view of the first 24 pages of tens of thousands of books published since 1949);
4. Local gazetteers/local histories (full text all free, I think);
5. Books published in the Min guo (Republican period, 1911-1949) (full text all free; 8172 titles or 8884 volumes);
6. Min guo periodicals (full text all free; 4329 titles);
7. Min guo (Republican period) laws/legal documents (full text all free; 8112 items or 29087 pages);
8. Photos of oracle bones, characters, New Year pictures, etc, (all free.);
9. Audio and video resources (158,000 audio items and 108,000 video items since 1987; only partially available)