writing,publication state and index compilation,summarizes the development course of American Chemical Abstracts in 95 years,and briefs the reasons of these changes and its contribution to the development of scientifi...writing,publication state and index compilation,summarizes the development course of American Chemical Abstracts in 95 years,and briefs the reasons of these changes and its contribution to the development of scientific & technical documentation.展开更多
The paper introduces the changes of the 7 th edition of International Patent Classification,including the number of classification entries,the number of indexing code entries and its basic structure.The relations of i...The paper introduces the changes of the 7 th edition of International Patent Classification,including the number of classification entries,the number of indexing code entries and its basic structure.The relations of its changes to human technical inventions are also discussed.展开更多
文摘writing,publication state and index compilation,summarizes the development course of American Chemical Abstracts in 95 years,and briefs the reasons of these changes and its contribution to the development of scientific & technical documentation.
文摘The paper introduces the changes of the 7 th edition of International Patent Classification,including the number of classification entries,the number of indexing code entries and its basic structure.The relations of its changes to human technical inventions are also discussed.