全文获取类型
收费全文 | 1077篇 |
免费 | 151篇 |
国内免费 | 4篇 |
专业分类
1232篇 |
出版年
2021年 | 16篇 |
2019年 | 10篇 |
2018年 | 8篇 |
2017年 | 8篇 |
2016年 | 20篇 |
2015年 | 34篇 |
2014年 | 42篇 |
2013年 | 37篇 |
2012年 | 62篇 |
2011年 | 39篇 |
2010年 | 26篇 |
2009年 | 34篇 |
2008年 | 26篇 |
2007年 | 34篇 |
2006年 | 41篇 |
2005年 | 42篇 |
2004年 | 23篇 |
2003年 | 27篇 |
2002年 | 33篇 |
2001年 | 26篇 |
2000年 | 23篇 |
1999年 | 25篇 |
1998年 | 21篇 |
1997年 | 12篇 |
1996年 | 15篇 |
1995年 | 18篇 |
1994年 | 9篇 |
1992年 | 21篇 |
1991年 | 17篇 |
1990年 | 24篇 |
1989年 | 24篇 |
1988年 | 31篇 |
1987年 | 32篇 |
1986年 | 27篇 |
1985年 | 29篇 |
1984年 | 21篇 |
1983年 | 26篇 |
1982年 | 18篇 |
1981年 | 22篇 |
1980年 | 11篇 |
1979年 | 17篇 |
1978年 | 18篇 |
1976年 | 11篇 |
1974年 | 12篇 |
1973年 | 20篇 |
1972年 | 12篇 |
1971年 | 15篇 |
1970年 | 11篇 |
1968年 | 8篇 |
1967年 | 9篇 |
排序方式: 共有1232条查询结果,搜索用时 15 毫秒
61.
62.
63.
Structures binding an antibody against tubulin from porcine brain were localized in the giant anastral mitotic apparatus of endosperm cells of the monocotyledonous plant, Leucojum aestivum, by indirect immunofluorescence microscopy. Both continuous and chromosomal spindle fibers were strongly stained. Postive fluorescence was also noted in polar cap regions and, in prometaphase stages, to some extent at the fragmented nuclear envelope. Intermingling and branching of subfiber elements was frequently noted. 相似文献
64.
Purinergic Signalling - 相似文献
65.
The discovery that genetic mutations in several cellular pathways can increase lifespan has lent support to the notion that pharmacological inhibition of aging pathways can be used to extend lifespan and to slow the onset of age‐related diseases. However, so far, only few compounds with such activities have been described. Here, we have conducted a chemical genetic screen for compounds that cause the extension of chronological lifespan of Schizosaccharomyces pombe. We have characterized eight natural products with such activities, which has allowed us to uncover so far unknown anti‐aging pathways in S. pombe. The ionophores monensin and nigericin extended lifespan by affecting vacuolar acidification, and this effect depended on the presence of the vacuolar ATPase (V‐ATPase) subunits Vma1 and Vma3. Furthermore, prostaglandin J2 displayed anti‐aging properties due to the inhibition of mitochondrial fission, and its effect on longevity required the mitochondrial fission protein Dnm1 as well as the G‐protein‐coupled glucose receptor Git3. Also, two compounds that inhibit guanosine monophosphate (GMP) synthesis, mycophenolic acid (MPA) and acivicin, caused lifespan extension, indicating that an imbalance in guanine nucleotide levels impinges upon longevity. We furthermore have identified diindolylmethane (DIM), tschimganine, and the compound mixture mangosteen as inhibiting aging. Taken together, these results reveal unanticipated anti‐aging activities for several phytochemicals and open up opportunities for the development of novel anti‐aging therapies. 相似文献
66.
Lutz?HamannEmail author Alexander?Koch Saubashya?Sur Nadja?Hoefer Christiane?Glaeser Susanne?Schulz Michael?Gross Andre?Franke Ute?N?thlings Kai?Zacharowski Ralf?R?Schumann 《Immunity & ageing : I & A》2013,10(1):43
Background
The pro-inflammatory status of the elderly triggers most of the age-related diseases such as cancer and atherosclerosis. Atherosclerosis, the leading cause world wide of morbidity and death, is an inflammatory disease influenced by life-style and genetic host factors. Stimuli such as oxLDL or microbial ligands have been proposed to trigger inflammation leading to atherosclerosis. It has recently been shown that oxLDL activates immune cells via the Toll-like receptor (TLR) 4/6 complex. Several common single nucleotide polymorphisms (SNPs) of the TLR system have been associated with atherosclerosis. To investigate the role of TLR-6 we analyzed the association of the TLR-6 SNP Pro249Ser with atherogenesis.Results
Genotyping of two independent groups with CAD, as well as of healthy controls revealed a significant association of the homozygous genotype with a reduced risk for atherosclerosis (odds ratio: 0.69, 95% CI 0.51-0.95, P?=?0.02). In addition, we found a trend towards an association with the risk of restenosis after transluminal coronary angioplasty (odds ratio: 0.53, 95% CI 0.24-1.16, P?=?0.12). In addition, first evidence is presented that the frequency of this protective genotype increases in a healthy population with age. Taken together, our results define a role for TLR-6 and its genetic variations in modulating the inflammatory response leading to atherosclerosis.Conclusions
These results may lead to a better risk stratification, and potentially to an improved prophylactic treatment of high-risk populations. Furthermore, the protective effect of this polymorphism may lead to an increase of this genotype in the healthy elderly and may therefore be a novel genetic marker for the well-being during aging.67.
Richard J. Franke 《The Yale journal of biology and medicine》2016,89(1):105-108
Palliative care is a quickly growing facet of modern medicine. While scientific advancements have broken new ground for the possibilities of end-of-life care, sensitive treatment of the patient as an individual has lagged behind and has frequently led to an unsatisfactory experience for patients, families, and the medical community at large. This essay argues that centralizing patients during the terminal phases of treatment by using humanistic perspectives has the potential to bring new meaning and improved effectiveness to patients and physicians alike. 相似文献
68.
The anabolic action of intermittent parathyroid hormone on cortical bone depends partly on its ability to induce nitric oxide‐mediated vasorelaxation in BALB/c mice
下载免费PDF全文
![点击此处可从《Cell biochemistry and function》网站下载免费的PDF全文](/ch/ext_images/free.gif)
S Gohin A Carriero C Chenu AA Pitsillides TR Arnett M Marenzana 《Cell biochemistry and function》2016,34(2):52-62
There is strong evidence that vasodilatory nitric oxide (NO) donors have anabolic effects on bone in humans. Parathyroid hormone (PTH), the only osteoanabolic drug currently approved, is also a vasodilator. We investigated whether the NO synthase inhibitor L‐NAME might alter the effect of PTH on bone by blocking its vasodilatory effect. BALB/c mice received 28 daily injections of PTH[1–34] (80 µg/kg/day) or L‐NAME (30 mg/kg/day), alone or in combination. Hindlimb blood perfusion was measured by laser Doppler imaging. Bone architecture, turnover and mechanical properties in the femur were analysed respectively by micro‐CT, histomorphometry and three‐point bending. PTH increased hindlimb blood flow by >30% within 10 min of injection (P < 0.001). Co‐treatment with L‐NAME blocked the action of PTH on blood flow, whereas L‐NAME alone had no effect. PTH treatment increased femoral cortical bone volume and formation rate by 20% and 110%, respectively (P < 0.001). PTH had no effect on trabecular bone volume in the femoral metaphysis although trabecular thickness and number were increased and decreased by 25%, respectively. Co‐treatment with L‐NAME restricted the PTH‐stimulated increase in cortical bone formation but had no clear‐cut effects in trabecular bone. Co‐treatment with L‐NAME did not affect the mechanical strength in femurs induced by iPTH. These results suggest that NO‐mediated vasorelaxation plays partly a role in the anabolic action of PTH on cortical bone. © 2016 The Authors. Cell Biochemistry and Function published by John Wiley & Sons, Ltd. 相似文献
69.
Melanie Kaiser Anja Penk Heike Franke Ute Krügel Wolfgang Nörenberg Daniel Huster Michael Schaefer 《Purinergic signalling》2016,12(3):453-463
Effective therapeutic measures against the development of brain edema, a life-threatening complication of cerebral ischemia, are necessary to improve the functional outcome for the patient. Here, we identified a beneficial role of purinergic receptor P2X7 activation in acute ischemic stroke. Involvement of P2X7 in the development of neurological deficits, infarct size, brain edema, and glial responses after ischemic cerebral infarction has been analyzed. Neurologic evaluation, magnetic resonance imaging, and immunofluorescence assays were used to characterize the receptor’s effect on the disease progress during 72 h after transient middle cerebral artery occlusion (tMCAO). Sham-operated animals were included in all experiments for control purposes. We found P2X7-deficient mice to develop a more prominent brain edema with a trend towards more severe neurological deficits 24 h after tMCAO. Infarct sizes, T2 times, and apparent diffusion coefficients did not differ significantly between wild-type and P2X7?/? animals. Our results show a characteristic spatial distribution of reactive glia cells with strongly attenuated microglia activation in P2X7?/? mice 72 h after tMCAO. Our data indicate that P2X7 exerts a role in limiting the early edema formation, possibly by modulating glial responses, and supports later microglia activation. 相似文献
70.