全文获取类型
收费全文 | 3157篇 |
免费 | 312篇 |
国内免费 | 1篇 |
出版年
2023年 | 10篇 |
2022年 | 5篇 |
2021年 | 72篇 |
2020年 | 36篇 |
2019年 | 32篇 |
2018年 | 54篇 |
2017年 | 51篇 |
2016年 | 91篇 |
2015年 | 163篇 |
2014年 | 159篇 |
2013年 | 181篇 |
2012年 | 231篇 |
2011年 | 208篇 |
2010年 | 150篇 |
2009年 | 119篇 |
2008年 | 171篇 |
2007年 | 204篇 |
2006年 | 179篇 |
2005年 | 203篇 |
2004年 | 194篇 |
2003年 | 162篇 |
2002年 | 167篇 |
2001年 | 48篇 |
2000年 | 39篇 |
1999年 | 50篇 |
1998年 | 61篇 |
1997年 | 28篇 |
1996年 | 41篇 |
1995年 | 26篇 |
1994年 | 32篇 |
1993年 | 26篇 |
1992年 | 26篇 |
1991年 | 20篇 |
1990年 | 11篇 |
1989年 | 4篇 |
1988年 | 16篇 |
1987年 | 16篇 |
1986年 | 12篇 |
1985年 | 14篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 14篇 |
1981年 | 10篇 |
1980年 | 4篇 |
1979年 | 14篇 |
1978年 | 8篇 |
1977年 | 8篇 |
1976年 | 13篇 |
1975年 | 10篇 |
1937年 | 3篇 |
排序方式: 共有3470条查询结果,搜索用时 0 毫秒
1.
2.
Protection of Mice against Lethal Coxsackievirus B3 Infection by Using DNA Immunization 总被引:27,自引:0,他引:27 下载免费PDF全文
Andreas Henke Elke Wagner J. Lindsay Whitton Roland Zell Axel Stelzner 《Journal of virology》1998,72(10):8327-8331
Vaccination with DNA and recombinant vaccinia viruses (rec.VV) has been studied with the coxsackievirus B3 (CVB3) model system. Plasmids encoding all structural proteins of CVB3, when injected intramuscularly, induced only low levels of virus-specific antibodies. However, DNA vaccination with the major structural protein VP1 protected 72.2% of mice from lethal challenge, whereas VP1 expressed by rec.VV was much less efficient. 相似文献
3.
4.
Jean-Michel Panoff Bouachanh Thammavongs Jean-Marie Laplace Axel Hartke Philippe Boutibonnes Yanick Auffray 《Cryobiology》1995,32(6)
The physiology of the cold-shock response in Lactococcus lactis subsp. lactis IL1403 at a subzero temperature, and cold-induced adaptation to heat shock, were investigated. Preincubation of cells at 8°C led to the development of cryotolerance, i.e., an enhanced capacity to survive exposure to freezing temperature (-20°C). Pretreatment with chemicals considered to be chaotropic agents did not induce cryotolerance or, in contrast, led to a decrease in survival capacity at -20°C. Interestingly, preincubation at 8°C led also to thermololerance to a 52°C challenge, but preincubation of cells at 42°C for 30 min did not improve their capacity to survive freezing-thawing exposure. These results demonstrate that cold- and heat-shock responses are physiologically linked by a complex relation. Furthermore, food processing at low temperature before subzero or heat treatment may need to be reconsidered. 相似文献
5.
Samir Jabari Alexandre B. M. da Silveira Enio C. de Oliveira Karl Quint André Wirries Winfried Neuhuber Axel Brehmer 《Cell and tissue research》2014,358(1):75-83
Chagasic megacolon is accompanied by extensive myenteric and, simultaneously, moderate submucosal neuron loss. Here, we examined changes of the innervation pattern of the lamina propria (LP) and muscularis mucosae (MM). Two alternating sets of cryosections were taken from seven non-chagasic colonic and seven chagasic megacolonic specimens (the latter included both the dilated megacolonic and the non-dilated transitional oral and anal zones) and were immunohistochemically triple-stained for smooth-muscle actin (SMA), synaptophysin (SYN) and glial acid protein S100 and, alternatively, for SMA, vasoactive intestinal peptide (VIP) and somatostatin (SOM). Subsequent image analysis and statistical evaluation of nervous tissue profile areas revealed that, in LP, the most extreme differences (i.e. increase in thickness or decrease in nerve, glia and muscle tissue profile area, respectively) compared with control values occurred in the dilated megacolonic zone itself. In contrast, the most extreme differences in the MM were in the anal-to-megacolonic zone (except the profile area of muscle tissue, which was lowest in the megacolonic zone). This parallels our previous results in the external muscle coat. A partial and selective survival of VIP-immunoreactive in contrast to SOM-immunoreactive nerve fibres was observed in both mucosal layers investigated. Thus, VIPergic nerve elements might be crucial for the maintenance of the mucosal barrier. The differential changes of neural tissue parameters in LP and MM might reflect a multifactorial rather than a pure neurogenic development of megacolon in chronic Chagas’ disease. 相似文献
6.
Professor Dr. Paul Buchner 《Zoomorphology》1957,46(5):481-528
Ohne ZusammenfassungAus der von der Deutschen Forschungsgemeinschaft eingerichteten, der Symbioseforschung dienenden Arbeitsstatte in Porto d'Ischia (Napoli). 相似文献
7.
N-Terminal Sequence of Pig Brain Choline Acetyltransferase Purified by a Rapid Procedure 总被引:6,自引:5,他引:1
Axel Braun Yves-Alain Barde Friedrich Lottspeich Werner Mewes Hans Thoenen 《Journal of neurochemistry》1987,48(1):16-21
A procedure is reported that allows the purification and amino terminal sequencing of pig brain choline acetyltransferase. The enzyme (present in extremely low amounts in this tissue) is eluted together with its antibody from an affinity column by a mild pH shift and the resulting enzyme-antibody complex separated by gel electrophoresis. The band corresponding to the enzyme is electroeluted from the gel using volatile solutions allowing the direct determination of the amino acid composition and partial sequence. The first 11 residues are: Pro-Ile-Leu-Glu-Lys-Thr-Pro-Pro-Lys-Met-Ala. 相似文献
8.
Helmut Krüger Werner Schr?der Klaus Buchner Ferdinand Hucho 《Journal of Protein Chemistry》1990,9(4):467-473
Inhibition of protein kinase C (PKC) by calmodulin is investigated and we describe the localization of inhibitory sequences within the calmodulin molecule. We present evidence that calmodulin inhibits PKC through an inhibition of the activation of PKC associated with lipid membranes: Binding of PKC to lipid vesicles is not affected, but activation is abolished. The potent calmodulin antagonist R24571 (calmidazol) did not affect the inhibition of PKC by calmodulin at concentrations up to 10–5 M. Two tryptic fragments of calmodulin were isolated which inhibited PKC. They were only slightly less potent than intact calmodulin with an IC50 of 6 µ M compared to 1 µ M of intact calmodulin. They were identified as Ser38-Arg74 and His107-Lys148. Each of the inhibiting fragments contains an intact Ca2+-binding domain with complete helix-loop-helix structure (EF hand). Other calmodulin peptides showed only weak inhibitory activity. Both fragments did not stimulate cAMP phosphodiesterase even at concentrations 100-fold higher than the calmodulin concentration needed for maximal stimulation. None of the fragments acted as a calmodulin antagonist. 相似文献
9.
10.
Buchner DM 《The Western journal of medicine》1988,148(2):198-199