全文获取类型
收费全文 | 13354篇 |
免费 | 1058篇 |
国内免费 | 2篇 |
专业分类
14414篇 |
出版年
2023年 | 69篇 |
2022年 | 156篇 |
2021年 | 270篇 |
2020年 | 160篇 |
2019年 | 192篇 |
2018年 | 259篇 |
2017年 | 253篇 |
2016年 | 411篇 |
2015年 | 666篇 |
2014年 | 766篇 |
2013年 | 924篇 |
2012年 | 1254篇 |
2011年 | 1159篇 |
2010年 | 703篇 |
2009年 | 620篇 |
2008年 | 893篇 |
2007年 | 929篇 |
2006年 | 777篇 |
2005年 | 757篇 |
2004年 | 671篇 |
2003年 | 638篇 |
2002年 | 629篇 |
2001年 | 109篇 |
2000年 | 78篇 |
1999年 | 103篇 |
1998年 | 144篇 |
1997年 | 88篇 |
1996年 | 75篇 |
1995年 | 70篇 |
1994年 | 71篇 |
1993年 | 71篇 |
1992年 | 52篇 |
1991年 | 47篇 |
1990年 | 42篇 |
1989年 | 26篇 |
1988年 | 24篇 |
1987年 | 22篇 |
1986年 | 23篇 |
1985年 | 15篇 |
1984年 | 22篇 |
1983年 | 19篇 |
1982年 | 9篇 |
1981年 | 18篇 |
1980年 | 14篇 |
1979年 | 10篇 |
1978年 | 11篇 |
1975年 | 8篇 |
1971年 | 11篇 |
1969年 | 8篇 |
1966年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
11.
12.
As revealed in earlier studies, the antinocifensive effect of morphine is brought about, among other things, with involvement of serotoninergic transmission mechanisms. In this context the role of the serotoninergic raphe-hippocampus system has been studied in this paper. Topical microinjections of serotonin into the dorsal hippocampus increased morphine analgesia in a dose-dependent fashion, while application into the striatum had no effect. Morphine injections into the median raphe nucleus in relatively low doses exert an antinocifensive effect which is inhibitable by methysergide. Lysergic acid diethylamide administered into the median raphe nucleus also abolished the effect of morphine in a dose-dependent manner. The results in connection with literature data lend support to the presumed integrative function of the serotoninergic raphe-hippocampus system in the mechanism of antinocifensive action of morphine. 相似文献
13.
14.
15.
16.
17.
18.
19.
Lee D. Major Thomas S. Partridge Joy Gardner Stephen J. Kent Robert de Rose Andreas Suhrbier Wayne A. Schroder 《PloS one》2013,8(2)
SerpinB2, also known as plasminogen activator inhibitor type 2, is a major product of activated monocytes/macrophages and is often strongly induced during infection and inflammation; however, its physiological function remains somewhat elusive. Herein we show that SerpinB2 is induced in peripheral blood mononuclear cells following infection of pigtail macaques with CCR5-utilizing (macrophage-tropic) SIVmac239, but not the rapidly pathogenic CXCR4-utilizing (T cell-tropic) SHIVmn229. To investigate the role of SerpinB2 in lentiviral infections, SerpinB2−/− mice were infected with EcoHIV, a chimeric HIV in which HIV gp120 has been replaced with gp80 from ecotropic murine leukemia virus. EcoHIV infected SerpinB2−/− mice produced significantly lower anti-gag IgG1 antibody titres than infected SerpinB2+/+ mice, and showed slightly delayed clearance of EcoHIV. Analyses of published microarray studies showed significantly higher levels of SerpinB2 mRNA in monocytes from HIV-1 infected patients when compared with uninfected controls, as well as a significant negative correlation between SerpinB2 and T-bet mRNA levels in peripheral blood mononuclear cells. These data illustrate that SerpinB2 can be induced by lentiviral infection in vivo and support the emerging notion that a physiological role of SerpinB2 is modulation of Th1/Th2 responses. 相似文献
20.