全文获取类型
收费全文 | 753篇 |
免费 | 55篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 11篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 7篇 |
2016年 | 7篇 |
2015年 | 23篇 |
2014年 | 26篇 |
2013年 | 44篇 |
2012年 | 57篇 |
2011年 | 61篇 |
2010年 | 26篇 |
2009年 | 21篇 |
2008年 | 50篇 |
2007年 | 67篇 |
2006年 | 58篇 |
2005年 | 47篇 |
2004年 | 50篇 |
2003年 | 30篇 |
2002年 | 46篇 |
2001年 | 7篇 |
2000年 | 3篇 |
1999年 | 15篇 |
1998年 | 13篇 |
1997年 | 12篇 |
1996年 | 10篇 |
1995年 | 6篇 |
1994年 | 9篇 |
1993年 | 9篇 |
1992年 | 11篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 9篇 |
1980年 | 5篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有808条查询结果,搜索用时 15 毫秒
21.
With so many neutrophins and receptors now known, how is our picture of neurotrophism changing? Recent studies on knockout mice have confirmed our expectations of neurotrophin action in neuronal development. A notable exception is the activation of TrkB, on motor neurons, by an unknown ligand. It is also clear that some neurotrophins have diverse activities and influence early developmental stages. There are interesting new data concerning the role of p75, the low affinity neurotrophin receptor, as a modulator of neurotrophin activity. Even more exciting are new studies on glia-derived neurotrophic factor (GDNF) which demonstrate that this growth factor acts as a potential protector of motor neurons and striatal dopaminergic neurons. 相似文献
22.
Anne-Marie Bourdeaux Yves Giudicelli Marie-Christine Rebourcet Joseph Nordmann Roger Nordmann 《Biochemical and biophysical research communications》1980,95(1):212-219
At concentrations corresponding to the levels usually reported in the blood of different species in the fed state, gastrin and pancreozymin but not secretin and vasoactive intestinal peptide, stimulate the lipoprotein lipase activity of adipose tissue from fasted rats. The enzyme response to gastrin is, like that to insulin, dependent on the presence of glucose and is not additive with the enzyme response to insulin. On the contrary, the effect of pancreozymin on lipoprotein lipase is glucoseindependent and is additive with the enzyme response to insulin. Both the effects of gastrin and pancreozymin depend on protein synthesis as shown by their suppression by cycloheximide. With isolated fat cells, gastrin increases both the releasable and non-releasable lipase activities whereas pancreozymin increases almost exclusively the non-releasable activity. The mechanisms and the possible physiological significance of these findings are discussed in relationship with the influence of insulin and the nutritional state on adipose tissue lipoprotein lipase. 相似文献
23.
24.
25.
Fabien Sénéchal Mélanie L'Enfant Jean-Marc Domon Emeline Rosiau Marie-Jeanne Crépeau Ogier Surcouf Juan Esquivel-Rodriguez Paulo Marcelo Alain Mareck Fran?ois Guérineau Hyung-Rae Kim Jozef Mravec Estelle Bonnin Elisabeth Jamet Daisuke Kihara Patrice Lerouge Marie-Christine Ralet Jér?me Pelloux Catherine Rayon 《The Journal of biological chemistry》2015,290(38):23320-23335
Pectin methylesterases (PMEs) catalyze the demethylesterification of homogalacturonan domains of pectin in plant cell walls and are regulated by endogenous pectin methylesterase inhibitors (PMEIs). In Arabidopsis dark-grown hypocotyls, one PME (AtPME3) and one PMEI (AtPMEI7) were identified as potential interacting proteins. Using RT-quantitative PCR analysis and gene promoter::GUS fusions, we first showed that AtPME3 and AtPMEI7 genes had overlapping patterns of expression in etiolated hypocotyls. The two proteins were identified in hypocotyl cell wall extracts by proteomics. To investigate the potential interaction between AtPME3 and AtPMEI7, both proteins were expressed in a heterologous system and purified by affinity chromatography. The activity of recombinant AtPME3 was characterized on homogalacturonans (HGs) with distinct degrees/patterns of methylesterification. AtPME3 showed the highest activity at pH 7.5 on HG substrates with a degree of methylesterification between 60 and 80% and a random distribution of methyl esters. On the best HG substrate, AtPME3 generates long non-methylesterified stretches and leaves short highly methylesterified zones, indicating that it acts as a processive enzyme. The recombinant AtPMEI7 and AtPME3 interaction reduces the level of demethylesterification of the HG substrate but does not inhibit the processivity of the enzyme. These data suggest that the AtPME3·AtPMEI7 complex is not covalently linked and could, depending on the pH, be alternately formed and dissociated. Docking analysis indicated that the inhibition of AtPME3 could occur via the interaction of AtPMEI7 with a PME ligand-binding cleft structure. All of these data indicate that AtPME3 and AtPMEI7 could be partners involved in the fine tuning of HG methylesterification during plant development. 相似文献
26.
Katrijn Van Laere Soraya C. França Hein Vansteenkiste Johan Van Huylenbroeck Kathy Steppe Marie-Christine Van Labeke 《Acta Physiologiae Plantarum》2011,33(4):1149-1156
In this study, we analysed morphological, anatomical and physiological effects of polyploidisation in Spathiphyllum
wallisii in order to evaluate possible interesting advantages of polyploids for ornamental breeding. Stomatal density was negatively
correlated with increased ploidy level. Stomatal size increased in polyploids. Tetraploid Spathiphyllum plants had more ovate and thicker leaves. The inflorescence of tetraploids had a more ovate and thicker spathum, a more cylindrical
spadix and a thicker but shorter flower stalk. Biomass production of the tetraploids was reduced, as expressed by lower total
dry weights, and tetraploids produced fewer shoots and leaves compared with their diploid progenitors. Furthermore, tetraploid
Spathiphyllum plants were more resistant to drought stress compared with diploid plants. After 15 days of drought stress, diploids showed
symptoms of wilting, while the tetraploids showed almost no symptoms. Further, measurements of stomatal resistance, leaf water
potential, relative water content and proline content indicated that the tetraploid genotypes were more resistant to drought
stress compared with the diploids. 相似文献
27.
28.
Marta Marchetti Delphine Capela Renaud Poincloux Nacer Benmeradi Marie-Christine Auriac Aurélie Le Ru Isabelle Maridonneau-Parini Jacques Batut Catherine Masson-Boivin 《PloS one》2013,8(2)
Rhizobia are symbiotic soil bacteria able to intracellularly colonize legume nodule cells and form nitrogen-fixing symbiosomes therein. How the plant cell cytoskeleton reorganizes in response to rhizobium colonization has remained poorly understood especially because of the lack of an in vitro infection assay. Here, we report on the use of the heterologous HeLa cell model to experimentally tackle this question. We observed that the model rhizobium Sinorhizobium meliloti, and other rhizobia as well, were able to trigger a major reorganization of actin cytoskeleton of cultured HeLa cells in vitro. Cell deformation was associated with an inhibition of the three major small RhoGTPases Cdc42, RhoA and Rac1. Bacterial entry, cytoskeleton rearrangements and modulation of RhoGTPase activity required an intact S. meliloti biosynthetic pathway for queuosine, a hypermodifed nucleoside regulating protein translation through tRNA, and possibly mRNA, modification. We showed that an intact bacterial queuosine biosynthetic pathway was also required for effective nitrogen-fixing symbiosis of S. meliloti with its host plant Medicago truncatula, thus indicating that one or several key symbiotic functions of S. meliloti are under queuosine control. We discuss whether the symbiotic defect of que mutants may originate, at least in part, from an altered capacity to modify plant cell actin cytoskeleton. 相似文献
29.
Engelhardt Ilonka C. Niklaus Pascal A. Bizouard Florian Breuil Marie-Christine Rouard Nadine Deau Florence Philippot Laurent Barnard Romain L. 《Plant and Soil》2021,461(1-2):151-162
Plant and Soil - Contrasting nutrient-acquisition strategies would explain why species differ in their distribution in relation to soil phosphorus (P) availability, promoting diversity. However,... 相似文献
30.
Bobby G. Ng Paulina Sosicka François Fenaille Annie Harroche Sandrine Vuillaumier-Barrot Mindy Porterfield Zhi-Jie Xia Shannon Wagner Michael J. Bamshad Marie-Christine Vergnes-Boiteux Sophie Cholet Stephen Dalton Anne Dell Thierry Dupré Mathieu Fiore Stuart M. Haslam Yohann Huguenin Tadahiro Kumagai Hudson H. Freeze 《American journal of human genetics》2021,108(6):1040-1052