全文获取类型
收费全文 | 1039篇 |
免费 | 58篇 |
出版年
2022年 | 10篇 |
2021年 | 23篇 |
2020年 | 11篇 |
2019年 | 19篇 |
2018年 | 40篇 |
2017年 | 38篇 |
2016年 | 26篇 |
2015年 | 53篇 |
2014年 | 40篇 |
2013年 | 56篇 |
2012年 | 81篇 |
2011年 | 90篇 |
2010年 | 51篇 |
2009年 | 34篇 |
2008年 | 71篇 |
2007年 | 76篇 |
2006年 | 60篇 |
2005年 | 49篇 |
2004年 | 48篇 |
2003年 | 38篇 |
2002年 | 44篇 |
2001年 | 9篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 8篇 |
1997年 | 10篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 11篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 10篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 6篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 5篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 5篇 |
1973年 | 5篇 |
1972年 | 5篇 |
1971年 | 1篇 |
排序方式: 共有1097条查询结果,搜索用时 15 毫秒
51.
52.
Sakai T Michikawa H Furuyama S Sugiya H 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2002,132(4):801-809
Guanosine 3′,5′-monophosphate (cGMP) is an intracellular messenger in various kinds of cell. We investigated the regulation of cGMP production by nitric oxide (NO) in rabbit submandibular gland cells. Methacholine, a muscarinic cholinergic agonist, stimulated cGMP production in a dose- and time-dependent manner, but the α-agonist phenylephrine, substance P and the β-agonist isoproterenol failed to evoke cGMP production. In fura-2-loaded cells, methacholine induced an increase in intracellular Ca2+ ([Ca2+]i) in a concentration-dependent manner, which was similar to that for cGMP production. When the external Ca2+ was chelated with EGTA, methacholine failed to induce cGMP production. Ca2+ ionophore A23187 and thapsigargin, which induce the increase in [Ca2+]i without activation of Ca2+-mobilizing receptors, mimicked the effect of methacholine. cGMP production induced by methacholine, A23187 and thapsigargin was clearly inhibited by NG-nitro-
-arginine methylester (L-NAME), a specific inhibitor of nitric oxide synthase (NOS). S-Nitroso-N-acetyl-
-penicillamine (SNAP), a NO donor, induced cGMP formation. In the lysate of rabbit submandibular gland cells, Ca2+-regulated nitric oxide synthase activity was detected. These findings suggest that cGMP production induced by the activation of muscarinic cholinergic receptors is regulated by NO generation via the increase in [Ca2+]i. 相似文献
53.
Maruyama H Higuchi N Nishikawa Y Kameda S Iino N Kazama JJ Takahashi N Sugawa M Hanawa H Tada N Miyazaki J Gejyo F 《The journal of gene medicine》2002,4(3):333-341
Background
High levels of foreign gene expression in mouse hepatocytes can be achieved by rapid tail vein injection of a large volume of a naked DNA solution, the ‘hydrodynamics‐based procedure’. Rats are more tolerant of the frequent phlebotomies required for monitoring blood parameters than mice, and thus are better for some biomedical research.Methods
We tested this technique for the delivery of a therapeutic protein in normal rats, using a rat erythropoietin (Epo) expression plasmid vector, pCAGGS‐Epo.Results
We obtained maximal Epo expression when the DNA solution was injected in a volume of 25 ml (approximately 100 ml/kg body weight) within 15 s. We observed a dose‐response relationship between serum Epo levels and the amount of injected DNA up to 800 µg. Using quantitative real‐time PCR, the vector‐derived Epo mRNA expression was mainly detected in the liver. When a lacZ expression plasmid was injected similarly, β‐galactosidase was exclusively detected in the liver, mainly in hepatocytes. Toxicity attributable to the technique was mild and transient, as assessed by histochemical analysis. Epo gene expression and erythropoiesis occurred with Epo gene transfer in a dose‐dependent manner, and persisted for at least 12 weeks, the last time point examined. Repeated administration of the plasmid DNA also effectively led to erythropoiesis.Conclusions
These results demonstrate that gene transfer into the liver via rapid tail vein injection can easily be achieved in the rat, which is more than 10 times larger than the mouse, and has significant value for gene function analysis in rats. Copyright © 2002 John Wiley & Sons, Ltd.54.
The phase-resetting experiment was applied to human periodic finger tapping to understand how its rhythm is controlled by
the internal neural clock that is assumed to exist. In the experiment, the right periodic tapping movement was disturbed transiently
by a series of left finger taps in response to impulsive auditory cues presented randomly at various phases within the tapping
cycle. After each left finger tap, the original periodic tapping was reestablished within several tapping cycles. Influences
of the disturbance on the periodic right finger tapping varied depending on the phase of the periodic right finger tapping
at which each left finger tap was made. It was confirmed that the periodic tapping was disturbed not by the auditory cues
but by the left finger taps. Based on this fact, in this paper each single left tap was considered as the stimulus, and the
phase of the periodic tapping of the right index finger when the left tap was executed as the phase of the stimulus. Responses
of the neural activities (magnetoencephalography, MEG), the tapping movement, and the corresponding muscle activities (electromyography)
were simultaneously measured. Phase-resetting curves (PRCs) representing the degree of phase reset as a function of the phase
of the stimulus were obtained both for the left sensorimotor cortex MEG response and for the right index finger tapping response.
The shapes of both PRCs were similar, suggesting that the phase reset of the left sensorimotor cortex activities and that
of the finger tapping rhythm were the same. Four out of eight subjects showed type-0 reset in Winfree's definition, and the
others showed type-1 reset. For general limit-cycle oscillators, type-0 reset is obtained for relatively strong perturbations
and type 1 for weak perturbations. It was shown that the transient response of MEG to the single left tap stimuli in type-0
subjects, where the phase was progressively reset, were different from those in type-1 subjects. Based on detailed analysis
of the differences, a neural network model for the phase reset of the tapping rhythm is proposed.
Received: 10 February 2000 / Accepted in revised form: 15 January 2002 相似文献
55.
Ogata Y Nakao S Shimizu E Matsuda-Honjyo Y Yamazaki M Furuyama S Sugiya H 《Cell biology international》2003,27(8):689-693
Bradykinin (1 microM) and histamine (100 microM) evoked an initial transient increase and a subsequent sustained increase in intracellular Ca(2+) concentration ([Ca(2+)](i)) in fura-2-loaded human gingival fibroblasts, which may be attributed to Ca(2+) release from intracellular stores and Ca(2+) entry from extracellular sites, respectively. In fibroblasts pretreated with tyrosine kinase inhibitors such as herbimycin A (1 microM) and tyrphostin 47 (20 microM), the sustained level of [Ca(2+)](i) induced by bradykinin and histamine increased, but not the initial peak level. In the absence of external Ca(2+), bradykinin and histamine induced only the transient increase in [Ca(2+)](i), but a subsequent addition of Ca(2+) to the medium resulted in a sustained increase in [Ca(2+)](i) caused by Ca(2+)entry. Thapsigargin, an inhibitor of Ca(2+)-ATPase in inositol 1,4,5-trisphosphate-sensitive Ca(2+) stores, mimicked the effect of bradykinin and histamine. In the fibroblasts pretreated with tyrosine kinase inhibitors, the bradykinin-, histamine- and thapsigargin-induced Ca(2+) entry was clearly enhanced, but not the transient [Ca(2+)](i) increase. Tyrosine phosphatase inhibitor benzylphosphonic acid (200 microM) had no effect on Ca(2+)entry or transient [Ca(2+)](i) increase. These results suggest that tyrosine phosphorylation is involved in Ca(2+) entry in human gingival fibroblasts. 相似文献
56.
-A new species of anisogammarid amphipod, Jesogammarus (Jesogammarus) mikadoi sp. nov., is described from freshwater habitats in northern Honshu, Japan. The species is distinguished from its congeners by having dorsal setae on pereonites 5-7 and pleonites 1-3. 相似文献
57.
Toshima G Kawamura S Araki T Torikata T 《Bioscience, biotechnology, and biochemistry》2003,67(3):540-546
The courses of the reaction catalyzed by guinea hen egg-white lysozyme (GHL), in which Asn113 and Arg114 at subsites E and F in hen egg-white lysozyme (HEL) are replaced by Lys and His, respectively, was studied with the substrate N-acetylglucosamine pentamer, (GlcNAc)5. Although GHL was found to retain the main-chain folding similar to HEL as judged from CD spectroscopy, the courses of GHL showed increased production of (GlcNAc)4 and reduced production of (GlcNAc)2 when compared with HEL. To identify critical residue(s) involved in the alteration in the courses of GHL, two mutant enzymes as to subsites E and F in HEL, N113K and R114H, were prepared by site-directed mutagenesis. Kinetic analysis of these mutants revealed that the mutation of Asn113 to Lys had little effect on the courses of HEL, while the Arg114 to His mutation completely reproduced the courses of GHL, demonstrating that His114 in GHL is the key residue responsible for the characteristic courses of GHL. Computer simulation of the reaction courses of the R114H mutant revealed that this substitution decreased not only the binding free energies for subsites E and F, but also the rate constant of transglycosylation. The Arg residue at position 114 may play an important role in the transglycosylation activity of HEL. 相似文献
58.
59.
60.
Molecular Cloning Reveals that the p160 Myb-Binding Protein Is a Novel, Predominantly Nucleolar Protein Which May Play a Role in Transactivation by Myb 总被引:8,自引:3,他引:5 下载免费PDF全文