全文获取类型
收费全文 | 7704篇 |
免费 | 83篇 |
国内免费 | 5篇 |
专业分类
教育 | 5290篇 |
科学研究 | 956篇 |
各国文化 | 71篇 |
体育 | 483篇 |
综合类 | 2篇 |
文化理论 | 51篇 |
信息传播 | 939篇 |
出版年
2021年 | 66篇 |
2020年 | 85篇 |
2019年 | 142篇 |
2018年 | 190篇 |
2017年 | 160篇 |
2016年 | 154篇 |
2015年 | 100篇 |
2014年 | 130篇 |
2013年 | 1345篇 |
2012年 | 140篇 |
2011年 | 140篇 |
2010年 | 126篇 |
2009年 | 112篇 |
2008年 | 141篇 |
2007年 | 110篇 |
2006年 | 124篇 |
2005年 | 101篇 |
2004年 | 119篇 |
2003年 | 104篇 |
2002年 | 91篇 |
2001年 | 125篇 |
2000年 | 123篇 |
1999年 | 109篇 |
1998年 | 74篇 |
1997年 | 76篇 |
1996年 | 96篇 |
1995年 | 72篇 |
1994年 | 63篇 |
1993年 | 97篇 |
1992年 | 126篇 |
1991年 | 127篇 |
1990年 | 119篇 |
1989年 | 107篇 |
1988年 | 104篇 |
1987年 | 114篇 |
1986年 | 102篇 |
1985年 | 116篇 |
1984年 | 97篇 |
1983年 | 103篇 |
1982年 | 108篇 |
1981年 | 77篇 |
1980年 | 78篇 |
1979年 | 107篇 |
1978年 | 96篇 |
1977年 | 90篇 |
1976年 | 82篇 |
1974年 | 69篇 |
1973年 | 73篇 |
1972年 | 60篇 |
1971年 | 60篇 |
排序方式: 共有7792条查询结果,搜索用时 0 毫秒
21.
22.
23.
F W Roper 《Bulletin of the Medical Library Association》1979,67(4):359-364
This paper reviews the current situation in library school education for medical librarianship in the United States and Canada based on information from a questionnaire sent to teachers of courses in medical librarianship in accredited library schools. Since 1939, when the first course devoted entirely to medical librarianship was offered at Columbia University, courses have been introduced into the curricula of at least forty-seven of the ALA-accredited library schools. In 1978 there were seventy courses available through forty-seven library schools. Possibilities for specialization in medical librarianship are examined. Course content is reviewed. Implications of the MLA certification examination for library school courses are explored. 相似文献
24.
John F. Fox Jr. 《Journal of Government Information》2004,30(4):470-481
This paper addresses several misunderstandings about the nature of the FBI's Central Records System. Although depicted in popular culture and much of FBI historiography as a tool for the Cold War suppression of American radicals, the FBI's records system grew out of Department of Justice systems already in place before J. Edgar Hoover became Director in 1924. The system grew in size and complexity according to the demands placed on it by the changing priorities of the FBI's criminal and intelligence missions, guided by a “progressive” drive for efficiency through centralization. 相似文献
25.
ABSTRACTLighting a cultural heritage artifact requires balancing visual perception with preventive conservation, by providing the best lighting (in terms of spectral distribution and quantity) to enable the viewer to appreciate details and color, while limiting photo-induced degradation. The paper outlines the methodology applied by a multi-disciplinary team while lighting the Shroud of Turin at its last public exhibition in 2015. The methodology considered the special requirements of the Shroud, including exposure to ultraviolet light, while providing appropriate display conditions that would meet audience expectations. The desired appearance (readability of the body image and color) was defined with the help of Shroud researchers and confirmed by subjective tests, while appropriate light levels for preservation were set in agreement with standard requirements and using knowledge of the degradation of linen in visible and UV light. The installation provided a controlled environment and a managed visitor route to the Shroud, assuring excellent perception of both details and color, with the lowest illuminance level about 15?lx. 相似文献
26.
27.
Tao Wang Ying Tong Wenjiao Xiao Lei Guo Brian F.Windley Tatiana Donskaya Shan Li Narantsetseg Tserendash Jianjun Zhang 《国家科学评论(英文版)》2022,9(5):167-178
Tracing the closure of oceans with irregular margins and the formation of an orocline are crucial for understanding plate reconstruction and continental assembly.The eastern Central Asian Orogenic Belt,where the Mongol-Okhotsk orocline is situated,is one of the world’s largest magmatic provinces.Using a large data set of U-Pb zircon ages,we updated the timing of many published igneous rocks,which allowed us to recognize tightly ’folded’ linear Carboniferous-Jurassic magmatic belts that wrap arou... 相似文献
28.
29.
30.