全文获取类型
收费全文 | 668篇 |
免费 | 35篇 |
专业分类
703篇 |
出版年
2022年 | 3篇 |
2021年 | 3篇 |
2017年 | 5篇 |
2016年 | 3篇 |
2015年 | 11篇 |
2014年 | 9篇 |
2013年 | 43篇 |
2012年 | 29篇 |
2011年 | 26篇 |
2010年 | 15篇 |
2009年 | 20篇 |
2008年 | 31篇 |
2007年 | 29篇 |
2006年 | 28篇 |
2005年 | 28篇 |
2004年 | 28篇 |
2003年 | 20篇 |
2002年 | 28篇 |
2001年 | 27篇 |
2000年 | 32篇 |
1999年 | 17篇 |
1998年 | 5篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 16篇 |
1990年 | 14篇 |
1989年 | 14篇 |
1988年 | 24篇 |
1987年 | 17篇 |
1986年 | 8篇 |
1985年 | 20篇 |
1984年 | 21篇 |
1983年 | 12篇 |
1982年 | 6篇 |
1981年 | 10篇 |
1980年 | 5篇 |
1979年 | 10篇 |
1978年 | 7篇 |
1977年 | 6篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1973年 | 5篇 |
1972年 | 5篇 |
1970年 | 4篇 |
1968年 | 3篇 |
排序方式: 共有703条查询结果,搜索用时 15 毫秒
621.
Hd3a and RFT1 are essential for flowering in rice 总被引:4,自引:0,他引:4
Komiya R Ikegami A Tamaki S Yokoi S Shimamoto K 《Development (Cambridge, England)》2008,135(4):767-774
622.
Although superiority of synthetic surfactant over animal-driven surfactant has been known, there is no synthetic surfactant commercially available at present. Many trials have been made to develop synthetic surfactant comparable in function to animal-driven surfactant. The efficacy of treatment with a new synthetic surfactant (CHF5633) containing dipalmitoylphosphatidylcholine, phosphatidylglycerol, SP-B analog, and SP-C analog was evaluated using immature newborn lamb model and compared with animal lung tissue-based surfactant Survanta. Lambs were treated with a clinical dose of 200 mg/kg CHF5633, 100 mg/kg Survanta, or air after 15 min initial ventilation. All the lambs treated with air died of respiratory distress within 90 min of age. During a 5 h study period, Pco(2) was maintained at 55 mmHg with 24 cmH(2)O peak inspiratory pressure for both groups. The preterm newborn lamb lung functions were dramatically improved by CHF5633 treatment. Slight, but significant superiority of CHF5633 over Survanta was demonstrated in tidal volume at 20 min and dynamic lung compliance at 20 and 300 min. The ultrastructure of CHF5633 was large with uniquely aggregated lipid particles. Increased uptake of CHF5633 by alveolar monocytes for catabolism was demonstrated by microphotograph, which might be associated with the higher treatment dose of CHF5633. The higher catabolism of CHF5633 was also suggested by the similar amount of surfactant lipid in bronchoalveolar lavage fluid (BALF) between CHF5633 and Survanta groups, despite the 2-fold higher treatment dose of CHF5633. Under the present ventilation protocol, lung inflammation was minimal for both groups, evaluated by inflammatory cell numbers in BALF and expression of IL-1β, IL-6, IL-8, and TNFα mRNA in the lung tissue. In conclusion, the new synthetic surfactant CHF5633 was effective in treating extremely immature newborn lambs with surfactant deficiency during the 5 h study period. 相似文献
623.
Quasielastic Light-Scattering Study on Changes in Sizes of Native White Membranes after Addition of Retinal 下载免费PDF全文
Jeffrey Marque Akira Ikegami Kenji Kubota Yasunori Tominaga Satoru Fujime 《Biophysical journal》1986,50(1):139-144
Aqueous suspensions of native white membranes from Halobacterium halobium, strain JW2N, have been studied by quasielastic light scattering. The intensity autocorrelation functions of polarized scattered light from suspensions of white membranes themselves and of white membranes after reconstitution with retinal were measured at various K2, K being the magnitude of the scattering vector. The first cumulant or the average decay rate of the correlation function was obtained by a cumulant expansion method. The first cumulant for the white membranes increased after retinal was added to the suspension. The first cumulants obtained before and after the addition of retinal were almost independent of pH in the range 7 to 11, and of temperature in the range 15° to 40°C after T/η scaling, η being the solvent viscosity. This suggests that photocycling in reconstituted membranes, induced by the probe laser-beam, did not cause any detectable change in spectra, and that the membrane flexibility, if present, was independent of the above conditions, so that the spectral changes after the addition of retinal could be attributed mostly to the changes in the sizes of the membranes. A theoretical formulation for the first cumulant for a rigid disk-like scatterer (Fujime, S. and K. Kubota, 1985, Biophys. Chem., 23:1-13.) was applied to the analysis of the spectra. The results suggest that the radii of the membrane patches decreased by several percent after the addition of retinal. 相似文献
624.
This paper presents a new game system formalism. The system describes both strategies and a game master (who computes scores in a given game system) in terms of λ-calculus. This formalism revisits the prisoner's dilemma game, to discuss how meta-strategies emerge in this classical game, even without repetition. We have also examined the evolution of meta-strategies in λ formalism. 相似文献
625.
Phenolic compounds from Gastrodia rhizome and relaxant effects of related compounds on isolated smooth muscle preparation 总被引:1,自引:0,他引:1
Hayashi J Sekine T Deguchi S Lin Q Horie S Tsuchiya S Yano S Watanabe K Ikegami F 《Phytochemistry》2002,59(5):513-519
Gastrol (1), together with 10 known phenolic compounds, has been isolated from the MeOH extract of the rhizomes of Gastrodia elata Blume (Orchidaceae), and their structures were elucidated by detailed spectral analyses including by 2D NMR spectroscopic analyses. The relaxant effects of these constituents on smooth muscle preparations isolated from guinea-pig ileum were also studied in order to reveal their characteristic pharmacological activities. 相似文献
626.
Ikegami M Dhami R Schuchman EH 《American journal of physiology. Lung cellular and molecular physiology》2003,284(3):L518-L525
Types A and B Niemann-Pick disease (NPD) are lipid storage disorders caused by the deficient activity of acid sphingomyelinase (ASM). In humans, NPD is associated with the dysfunction of numerous organs including the lung. Gene targeting of the ASM gene in transgenic mice produced an animal model with features typical of NPD, including pulmonary inflammation. To assess mechanisms by which ASM perturbed lung function, we studied lung morphology, surfactant content, and metabolism in ASM-deficient mice in vivo. Pulmonary inflammation, with increased cellular infiltrates and the accumulation of alveolar material, was associated with alterations in surfactant content. Saturated phosphatidylcholine (SatPC) content was increased twofold, and sphingomyelin content was increased 5.5-fold in lungs of the ASM knockout (ASMKO) mice. Additional sphingomyelin enhanced the sensitivity of surfactant inhibition by plasma proteins. Clearance of SatPC from the lungs of ASMKO mice was decreased. Catabolism of SatPC by alveolar macrophages from the ASMKO mouse was significantly decreased, likely accounting for decreased pulmonary SatPC in vivo. In summary, ASM is required for normal surfactant catabolism by alveolar macrophages in vivo. Alterations in surfactant composition, including increased sphingomyelin content, contributed to the abnormal surfactant function observed in the ASM-deficient mouse. 相似文献
627.
Fujiwara N Miyamoto Y Ogasahara K Takahashi M Ikegami T Takamiya R Suzuki K Taniguchi N 《The Journal of biological chemistry》2005,280(6):5061-5070
Although more than 100 mutations have been identified in the copper/zinc superoxide dismutase (Cu/Zn-SOD) in familial amyotrophic lateral sclerosis (FALS), the mechanism responsible for FALS remains unclear. The finding of the present study shows that FALS-causing mutant Cu/Zn-SOD proteins (FALS mutant SODs), but not wild-type SOD, are barely detected by three monoclonal antibodies (mAbs) in Western blot analyses. The enzyme-linked immunosorbent assay for denatured FALS mutant SODs by dithiothreitol, SDS, or heat treatment also showed a lowered immunoreactivity against the mAbs compared with wild-type SOD. Because all the epitopes of these mAbs are mapped within the Greek key loop (residues 102-115 in human Cu/Zn-SOD), these data suggest that different conformational changes occur in the loop between wild-type and FALS mutant SODs during the unfolding process. Circular dichroism measurements revealed that the FALS mutant SODs are sensitive to denaturation by dithiothreitol, SDS, or heat treatment, but these results do not completely explain the different recognition by the mAbs between wild-type and FALS mutant SODs under the denatured conditions. The study on the conformational changes in local areas monitoring with mAbs may provide a new insight into the etiology of FALS. 相似文献
628.
Hosoya K Watabe Y Ikegami T Tanaka N Kubo T Sano T Kaya K 《Biosensors & bioelectronics》2004,20(6):1185-1189
Uniformly sized polymeric separation media were prepared using o- or p-xylene as porogenic template to investigate chromatographic selectivity towards tetra-chlorinated dibenzo-p-dioxins (TCDDs). TCDDs having chlorine atoms at ortho positions of phenyl rings were selectively retained on stationary phase prepared with o-xylene as porogenic template, while TCDDs having chlorine atoms at para positions of phenyl ring were found to be retained selectively on the stationary phase imprinted by the porogenic template, p-xylene. Slightly longer cross-linking agent afforded chromatographically selective retention for larger TCDD isomers. It was also found that positional relationship between substituted chlorine atoms was also important for chromatographic recognition. 相似文献
629.
Jae Hong Im Takashi Nakane Hiroshi Yanagishita Toru Ikegami Dai Kitamoto 《BMC biotechnology》2001,1(1):5-7
Background
There have been many attempts to develop new materials with stability and high affinity towards immunoglobulins. Some of glycolipids such as gangliosides exhibit a high affinity toward immunoglobulins. However, it is considerably difficult to develop these glycolipids into the practical separation ligand due to their limited amounts. We thus focused our attention on the feasible use of "mannosylerythritol lipid A", a yeast glycolipid biosurfactant, as an alternative ligand for immunoglobulins, and undertook the investigation on the binding between mannosylerythritol lipid A (MEL-A) and human immunoglobulin G (HIgG). 相似文献630.