4. Main ways to obtain full text A. Printed literature B. Online version of the full-text database C. The Open access (Open Access) sites D. Interlibrary loan and document transfer services to obtain the full text 5. Open access to the english name is OA, which can be freely available on the public Internet, allowing any user A.read B.download C.duplicate D.seek 6. According to the processing level of the document,the types include: A.primary document B.secondary source C.tertiary publication D. Four literature 7. Secondary literature includes A.catalogue B.bibliographical reference C.abstract D.index