全文获取类型
收费全文 | 16969篇 |
免费 | 1213篇 |
出版年
2023年 | 125篇 |
2022年 | 80篇 |
2021年 | 249篇 |
2020年 | 217篇 |
2019年 | 236篇 |
2018年 | 426篇 |
2017年 | 404篇 |
2016年 | 506篇 |
2015年 | 672篇 |
2014年 | 730篇 |
2013年 | 1034篇 |
2012年 | 1351篇 |
2011年 | 1350篇 |
2010年 | 830篇 |
2009年 | 670篇 |
2008年 | 1101篇 |
2007年 | 1132篇 |
2006年 | 1079篇 |
2005年 | 987篇 |
2004年 | 969篇 |
2003年 | 897篇 |
2002年 | 787篇 |
2001年 | 186篇 |
2000年 | 246篇 |
1999年 | 181篇 |
1998年 | 150篇 |
1997年 | 89篇 |
1996年 | 95篇 |
1995年 | 113篇 |
1994年 | 89篇 |
1993年 | 82篇 |
1992年 | 96篇 |
1991年 | 76篇 |
1990年 | 67篇 |
1989年 | 54篇 |
1988年 | 50篇 |
1987年 | 49篇 |
1986年 | 37篇 |
1985年 | 48篇 |
1984年 | 61篇 |
1983年 | 42篇 |
1982年 | 54篇 |
1981年 | 54篇 |
1980年 | 53篇 |
1979年 | 45篇 |
1978年 | 48篇 |
1977年 | 39篇 |
1976年 | 42篇 |
1975年 | 39篇 |
1974年 | 28篇 |
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
1.
2.
Konstantinos Arapis Jean Baptiste Cavin Laura Gillard Fran?oise Cluzeaud Philippe Lettéron Robert Ducroc Johanne Le Beyec Muriel Hourseau Anne Couvelard Jean-Pierre Marmuse Maude Le Gall André Bado 《PloS one》2015,10(3)
Whereas the remodeling of intestinal mucosa after bariatric surgeries has been the matter of numerous studies to our knowledge, very few reported on the remodeling of the residual gastric mucosa. In this study, we analyzed remodeling of gastric mucosa after Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) in rats. Diet-induced obese rats were subjected to RYGB, VSG or sham surgical procedures. All animals were assessed for food intake, body-weight, fasting blood, metabolites and hormones profiling, as well as insulin and glucose tolerance tests before and up to 5 weeks post-surgery. Remodeling of gastric tissues was analyzed by routine histology and immunohistochemistry studies, and qRT-PCR analyses of ghrelin and gastrin mRNA levels. In obese rats with impaired glucose tolerance, VSG and RYGB caused substantial weight loss and rats greatly improved their oral glucose tolerance. The remaining gastric mucosa after VSG and gastric pouch (GP) after RYGB revealed a hyperplasia of the mucous neck cells that displayed a strong immunoreactivity for parietal cell H+/K+-ATPase. Ghrelin mRNA levels were reduced by 2-fold in remaining fundic mucosa after VSG and 10-fold in GP after RYGB. In the antrum, gastrin mRNA levels were reduced after VSG in line with the reduced number of gastrin positive cells. This study reports novel and important observations dealing with the remaining gastric mucosa after RYGB and VSG. The data demonstrate, for the first time, a hyperplasia of the mucous neck cells, a transit cell population of the stomach bearing differentiating capacities into zymogenic and peptic cells. 相似文献
3.
Coralie Fouquet Jean-Fran?ois Gilles Nicolas Heck Marc Dos Santos Richard Schwartzmann Vidjeacoumary Cannaya Marie-Pierre Morel Robert Stephen Davidson Alain Trembleau Susanne Bolte 《PloS one》2015,10(3)
Resolution, high signal intensity and elevated signal to noise ratio (SNR) are key issues for biologists who aim at studying the localisation of biological structures at the cellular and subcellular levels using confocal microscopy. The resolution required to separate sub-cellular biological structures is often near to the resolving power of the microscope. When optimally used, confocal microscopes may reach resolutions of 180 nm laterally and 500 nm axially, however, axial resolution in depth is often impaired by spherical aberration that may occur due to refractive index mismatches. Spherical aberration results in broadening of the point-spread function (PSF), a decrease in peak signal intensity when imaging in depth and a focal shift that leads to the distortion of the image along the z-axis and thus in a scaling error. In this study, we use the novel mounting medium CFM3 (Citifluor Ltd., UK) with a refractive index of 1.518 to minimize the effects of spherical aberration. This mounting medium is compatible with most common fluorochromes and fluorescent proteins. We compare its performance with established mounting media, harbouring refractive indices below 1.500, by estimating lateral and axial resolution with sub-resolution fluorescent beads. We show furthermore that the use of the high refractive index media renders the tissue transparent and improves considerably the axial resolution and imaging depth in immuno-labelled or fluorescent protein labelled fixed mouse brain tissue. We thus propose to use those novel high refractive index mounting media, whenever optimal axial resolution is required. 相似文献
4.
Antoine Poncet Baris Gencer Marc Blondon Marianne Gex-Fabry Christophe Combescure Dipen Shah Peter J. Schwartz Marie Besson Fran?ois R. Girardin 《PloS one》2015,10(6)
ImportanceSudden cardiac death is a leading cause of mortality in psychiatric patients. Long QT (LQT) is common in this population and predisposes to Torsades-de-Pointes (TdP) and subsequent mortality.ObjectiveTo estimate the cost-effectiveness of electrocardiographic screening to detect LQT in psychiatric inpatients.ResultsIn the base-case scenario, the numbers of patients needed to screen were 1128 and 2817 to avoid one TdP and one death, respectively. The ICER of systematic ECG screening was $8644 (95%CI, 3144-82 498) per QALY. The probability of cost-effectiveness was 96% at a willingness-to-pay of $50 000 for one QALY. In sensitivity analyses, results were sensitive to the case-fatality of TdP episodes and to the TdP reduction following the diagnosis of LQT.
Conclusion and Relevance
In psychiatric hospitals, performing systematic ECG screening at admission help reduce the number of sudden cardiac deaths in a cost-effective fashion. 相似文献5.
6.
7.
α‐ l‐iduronidase gene‐based therapy using the phiC31 system to treat mucopolysaccharidose type I mice 下载免费PDF全文
Roberta Sessa Stilhano Priscila Keiko Matsumoto Martin Suely Maymone de Melo Vivian Yochiko Samoto Giovani Bravin Peres Yara Maria Correa da Silva Michelacci Flavia Helena da Silva Vanessa Gonçalves Pereira Vania D'Almeida Adriana Taveira da Cruz Miriam Galvonas Jasiulionis Sang Won Han 《The journal of gene medicine》2015,17(1-2):1-13
8.
Luciano Jacob Corrêa Alberto Colli Badino Antonio José Gonçalves Cruz 《Bioprocess and biosystems engineering》2016,39(5):825-833
The minimization of costs in the distillation step of lignocellulosic ethanol production requires the use of a high solids loading during the enzymatic hydrolysis to obtain a more concentrated glucose liquor. However, this increase in biomass can lead to problems including increased mass and heat transfer resistance, decreased cellulose conversion, and increased apparent viscosity with the associated increase in power consumption. The use of fed-batch operation offers a promising way to circumvent these problems. In this study, one batch and four fed-batch strategies for solids and/or enzyme feeding during the enzymatic hydrolysis of sugarcane bagasse were evaluated. Determinations of glucose concentration, power consumption, and apparent viscosity were made throughout the experiments, and the different strategies were compared in terms of energy efficiency (mass of glucose produced according to the energy consumed). The best energy efficiency was obtained for the strategy in which substrate and enzyme were added simultaneously (0.35 kgglucose kWh?1). This value was 52 % higher than obtained in batch operation. 相似文献
9.
10.
Bruno Kieffer Patrice Koehl Serge Plaue Jean-François Lefèvre 《Journal of biomolecular NMR》1993,3(1):91-112
Summary We have investigated the dynamics and structural behaviour of two antigenic peptides using 1H NMR. The two cyclic peptides mimic the antigenic site A of influenza haemagglutinin protein; they only differ in the way they were cyclized and in the size of their respective linkers. Homonuclear relaxation parameters extracted from a complete NOE matrix were interpreted in terms of local dynamics. A set of distance constraints was deduced from these parameters which allowed 3D models to be constructed using distance geometry. NOE back-calculation was used to check the validity of the final models. Strong variations of internal motion amplitude have been found in both peptides along their backbone. Motions with high amplitudes have been localized in the Gly-Pro-Gly sequence which forms a -turn in both structures.Abbreviations DSS
3-(trimethylsilyl)-1-propanesulfonic acid
- D-loop
aspartic acid loop
- ELISA
enzyme-linked immunoabsorbent assay
- f.i.d
free induction decay
- HOHAHA
homonuclear Hartmann-Hahn spectroscopy
- HPLC
high pressure liquid chromatography
- K-loop
lysine loop
- NMR
nuclear magnetic resonance
- NOE
nuclear Overhauser enhancement
- NOESY
nuclear Overhauser enhancement spectroscopy
- r.m.s.d.
root-mean-square deviation of atomic positions 相似文献