全文获取类型
收费全文 | 842篇 |
免费 | 67篇 |
出版年
2024年 | 2篇 |
2023年 | 6篇 |
2022年 | 11篇 |
2021年 | 16篇 |
2020年 | 12篇 |
2019年 | 10篇 |
2018年 | 11篇 |
2017年 | 11篇 |
2016年 | 20篇 |
2015年 | 39篇 |
2014年 | 28篇 |
2013年 | 53篇 |
2012年 | 58篇 |
2011年 | 67篇 |
2010年 | 36篇 |
2009年 | 31篇 |
2008年 | 46篇 |
2007年 | 66篇 |
2006年 | 41篇 |
2005年 | 45篇 |
2004年 | 39篇 |
2003年 | 43篇 |
2002年 | 29篇 |
2001年 | 9篇 |
2000年 | 14篇 |
1999年 | 14篇 |
1998年 | 11篇 |
1997年 | 9篇 |
1996年 | 15篇 |
1995年 | 9篇 |
1994年 | 4篇 |
1993年 | 8篇 |
1992年 | 18篇 |
1991年 | 10篇 |
1990年 | 9篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 1篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1974年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有909条查询结果,搜索用时 15 毫秒
901.
Massimo Aureli Maura Samarani Nicoletta Loberto Elena Chiricozzi Laura Mauri Sara Grassi Domitilla Schiumarini Alessandro Prinetti Sandro Sonnino 《Glycoconjugate journal》2018,35(4):397-402
Sphingolipid metabolism is an intricate network of several interdependent and co-regulated pathways. In addition to the mainstream biosynthetic and catabolic pathways, several processes, even if less important in contributing to the final tissue sphingolipid composition from the quantitative point of view, might become relevant when sphingolipid metabolism is for any reason dysregulated and concur to the onset of neuronal pathologies. The main subcellular sites involved in the mainstream metabolic pathway are represented by the Golgi apparatus (for the biosynthesis) and by the lysosomes (for catabolism). On the other hand, the minor collateral pathways are associated with the plasma membrane and membranes of other organelles, and likely play important roles in the local regulation of membrane dynamics and contribute to maintain a perfect membrane organization functional to the physiology of the cell. In this review, we will consider few aspects of the sphingolipid metabolic pathway depending by the dynamic of the membranes that seems to become relevant in neurodegenerative diseases. 相似文献
902.
903.
904.
P Ascenzi M Coletta A Desideri R Petruzzelli F Polizio M Bolognesi S G Condò B Giardina 《Journal of inorganic biochemistry》1992,45(1):31-37
The spectroscopic (EPR and absorbance) properties of the nitric oxide derivative of ferrous man, horse, buffalo, deer, mouflon, musk ox, ox, and reindeer hemoglobin (HbNO) have been investigated in the absence of any allosteric effector at pH 6.5 (in 0.1 M 2-[N-morpholino]ethanesulphonic acid/NaOH chloride-free buffer system), as well as at 100 K and/or 20 degrees C. Man and horse HbNO show spectroscopic properties that are generally taken as typical of the high affinity state of ferrous tetrameric Hb's; on the other hand, the spectroscopic properties of ruminant (i.e., buffalo, deer, mouflon, musk ox, ox, and reindeer) HbNO are characteristic of the low affinity conformation. These results are in keeping with the functional properties of the mammalian Hb's considered and have been related to the peculiar low oxygen affinity of ruminant Hb's. 相似文献
905.
906.
Francesca Zambianchi Stefano Raimondi Piero Pasta Giacomo Carrea Nicoletta Gaggero John M. Woodley 《Journal of Molecular Catalysis .B, Enzymatic》2004,31(4-6):165-171
Both whole cells of recombinant Escherichia coli TOP10, overexpressing cyclohexanone monooxygenase (CHMO) and isolated cyclohexanone monooxygenase, were used to carry out the enantioselective oxidation of 1,3-dithiane (1) to (R)-1,3-dithiane-1-oxide (2). The two biocatalysts were evaluated under various experimental conditions (e.g., shaken flask or bioreactor; non-bound or resin-adsorbed substrate; different substrate concentrations) in terms of volumetric productivity and enantioselectivity. While productivity was similar in the two cases (up to 0.58 g L−1 h−1), the optical purity of the product was much higher with the isolated enzyme (up to 98% e.e.) than with the whole cell biocatalyst (up to 85% e.e.). 相似文献
907.
Veronique van den Berghe Elke Stappers Bram Vandesande Jordane Dimidschstein Roel Kroes Annick Francis Andrea Conidi Flore Lesage Ruben Dries Silvia Cazzola Geert Berx Nicoletta Kessaris Pierre Vanderhaeghen Wilfred van IJcken Frank G. Grosveld Steven Goossens Jody J. Haigh Gord Fishell Eve Seuntjens 《Neuron》2013,77(1):70-82
908.
The effect of inositol hexakisphosphate, 2,3-diphosphoglycerate, dextran sulphate, and heparin on the spectroscopic (absorbance, circular dichroism, EPR) properties of the nitric oxide derivative of ferrous dromedary (Camelus dromedarius) hemoglobin was investigated. The results obtained show that: (i) all polyanions bind to the protein at the same sites, but with different affinities; (ii) polyanions affect the protein conformation of the ferrous nitrosyl derivative in a different way with respect to aquo-ferric and ferrous oxy dromedary hemoglobin; and (iii) the data obtained provide further independent evidence for the existence in dromedary hemoglobin of two functionally distinct polyanion binding sites that affect the conformational equilibrium of the protein in opposite ways. 相似文献
909.
Summary X-ray absorption spectroscopy has been applied to the in vivo examination of copper-resistant yeast cells. The in vivo structure of the metal-binding site of the accumulated copper has been compared to that of the purified yeast thionein. Analysis of the EXAFS spectra performed on intact yeast cells indicates that the accumulated copper is univalent and is exclusively coordinated to sulfur atoms at a distance of 219 pin with an average coordination number of 2. In contrast, the purified protein indicates a univalent copper trigonally coordinated to sulfur at a distance of 221 pm. These discrepancies are discussed in terms of copper location in the resistant yeast cells. 相似文献