全文获取类型
收费全文 | 817124篇 |
免费 | 96705篇 |
国内免费 | 385篇 |
专业分类
914214篇 |
出版年
2016年 | 8990篇 |
2015年 | 12323篇 |
2014年 | 14770篇 |
2013年 | 20990篇 |
2012年 | 23402篇 |
2011年 | 23521篇 |
2010年 | 15985篇 |
2009年 | 14887篇 |
2008年 | 21217篇 |
2007年 | 22047篇 |
2006年 | 20650篇 |
2005年 | 20146篇 |
2004年 | 19955篇 |
2003年 | 19468篇 |
2002年 | 18688篇 |
2001年 | 33362篇 |
2000年 | 33562篇 |
1999年 | 27076篇 |
1998年 | 10089篇 |
1997年 | 10483篇 |
1996年 | 10135篇 |
1995年 | 9648篇 |
1994年 | 9571篇 |
1993年 | 9462篇 |
1992年 | 23567篇 |
1991年 | 23207篇 |
1990年 | 22768篇 |
1989年 | 22135篇 |
1988年 | 20780篇 |
1987年 | 20130篇 |
1986年 | 18816篇 |
1985年 | 19149篇 |
1984年 | 16123篇 |
1983年 | 14255篇 |
1982年 | 11135篇 |
1981年 | 10501篇 |
1980年 | 9759篇 |
1979年 | 16232篇 |
1978年 | 12740篇 |
1977年 | 11853篇 |
1976年 | 11313篇 |
1975年 | 12488篇 |
1974年 | 13237篇 |
1973年 | 13032篇 |
1972年 | 12136篇 |
1971年 | 10793篇 |
1970年 | 9504篇 |
1969年 | 9197篇 |
1968年 | 8349篇 |
1967年 | 7299篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
M R Chandler 《Perspectives in biology and medicine》1991,35(1):105-115
Over the past 10 years the AIDS crisis has produced a large volume of writing. Much of this is documentary. Dozens of studies of AIDS from various clinical and political perspectives have been complemented by just as many published diaries, autobiographies, novels, plays, and poems. A few of these works have risen to the surface not only as extraordinarily valuable testimonies to the changes AIDS has wrought in individual and collective life but also as first-rate literary works, worth reading because beyond their immediate purposes they articulate with extraordinary lucidity and compassion some deep truths about the human--and the modern--condition. Paul Monette's Borrowed Time is among the most distinctive of those. It speaks not only for the community of people with AIDS and those who support them but for a generation. 相似文献
62.
63.
64.
65.
66.
67.
68.
69.
Metabolic pathways involved in the oxidation of isopropanol into acetone by the intact rat 总被引:3,自引:0,他引:3
Isopropanol administered in a large (6 g/kg, orally) as well as in a lower dose (1 g/kg, I.P.) is slowly oxidized into acetone by the intact rat. Using two inhibitors, 3 amino-1,2,4-triazole and pyrazole, investigations on the hepatic enzymatic system involved in the oxidation of isopropanol show that catalase does not play an important part in this pathway, contrary to alcohol dehydrogenase which is the major enzyme responsible for this oxidation. Although isopropanol oxidation is mainly catalysed in the liver through alcohol dehydrogenase, no alteration of the hepatic extramitochondrial redox state occurs after the administration of a large as well as of a lower dose of isopropanol. From these experiments it may be concluded that alterations of the liver NAD+/NADH ratio, which seem to play an important part in the ethanol induced fatty liver, are not involved in the isopropanol induced one. 相似文献
70.