全文获取类型
收费全文 | 152篇 |
免费 | 17篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 5篇 |
2016年 | 6篇 |
2015年 | 7篇 |
2014年 | 5篇 |
2013年 | 6篇 |
2012年 | 10篇 |
2011年 | 12篇 |
2010年 | 3篇 |
2009年 | 5篇 |
2008年 | 14篇 |
2007年 | 9篇 |
2006年 | 13篇 |
2005年 | 6篇 |
2003年 | 4篇 |
2002年 | 9篇 |
2001年 | 5篇 |
2000年 | 6篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1977年 | 1篇 |
排序方式: 共有169条查询结果,搜索用时 15 毫秒
41.
Safety assessment of transgenic potatoes with soybean glycinin by feeding studies in rats 总被引:11,自引:0,他引:11
Hashimoto W Momma K Yoon HJ Ozawa S Ohkawa Y Ishige T Kito M Utsumi S Murata K 《Bioscience, biotechnology, and biochemistry》1999,63(11):1942-1946
Feeding studies of transgenic potatoes with native and designed soybean glycinins in rats were done for four weeks. The designed glycinin has four additional methioninyl residues in the middle of the glycinin molecule. Rats were divided into four groups fed (I) only a commercial diet, (II) the diet plus non-transgenic potatoes, (III) the diet plus transgenic potatoes with native glycinin, and (IV) the diet plus transgenic potatoes with designed glycinin. Rats were fed 2,000 mg/kg-weight potatoes every day by oral administration. During the period tested, rats in each group (groups II, III, and IV) grew well without marked differences in appearance, food intake, body weight, or in cumulative body weight gain. No significant differences were also found in blood count, blood composition, and in internal organ weights among the rats after feeding potatoes (groups II, III, and IV) for four weeks. Necropsy at the end of experiment indicated neither pathologic symptoms in all rats tested nor histopathological abnormalities in liver and kidney. Judging from these results, the transgenic potatoes with glycinins are confirmed to have nearly the same nutritional and biochemical characteristics as non-transgenic one. 相似文献
42.
43.
Shunsaku Miyagi 《Landscape and Ecological Engineering》2005,1(1):71-76
This study presents a scenario in which recent development of landscape design based on modernism and modernists works is depicted in conjunction with its possible contribution toward nature restoration. Spatial pattern found in modernists works enhanced the designers understanding of landscape pattern underlying the land and environment at an extensive scale. In search of solid ground for pattern making, landscape designers further investigated the environmental system and its structure. A morphological approach employed in the discourse of landscape ecology gives a theoretical foundation to those endeavors. Also, the process through which the environmental system functions and is maintained becomes another potential field of design expression in landscape. Detailed studies of several works and p landscape design projects, which have already indicated a direction of development, will promote a productive and creative co-relationship between landscape design and nature restoration.This revised version was published online in April 2005 with corrections to keywords. 相似文献
44.
Inorganic polyphosphate and polyphosphate kinase: their novel biological functions and applications 总被引:5,自引:0,他引:5
In this review, we discuss the following two subjects: 1) the physiological function of polyphosphate (poly(P)) as a regulatory factor for gene expression in Escherichia coli, and 2) novel functions of E. coli polyphosphate kinase (PPK) and their applications. With regard to the first subject, it has been shown that E. coli cells in which yeast exopolyphosphatase (poly(P)ase), PPX1, was overproduced reduced resistance to H2O2 and heat shock as did a mutant whose polyphosphate kinase gene is disrupted. Sensitivity to H2O2 and heat shock evinced by cells that overproduce PPX1 is attributed to depressed levels of rpoS expression. Since rpoS is a central element in a regulatory network that governs the expression of stationary-phase-induced genes, poly(P) affects the expression of many genes through controlling rpoS expression. Furthermore, poly(P) is also involved in expression of other stress-inducible genes that are not directly regulated by rpoS. The second subject includes the application of novel functions of PPK for nucleoside triphosphate (NTP) regeneration. Recently E. coli PPK has been found to catalyze the kination of not only ADP but also other nucleoside diphosphates using poly(P) as a phospho-donor, yielding NTPs. This nucleoside diphosphate kinase-like activity of PPK was confirmed to be available for NTP regeneration essential for enzymatic oligosaccharide synthesis using the sugar nucleotide cycling method. PPK has also been found to express a poly(P):AMP phosphotransferase activity by coupling with adenylate kinase (ADK) in E. coli. The ATP-regeneration system consisting of ADK, PPK, and poly(P) was shown to be promising for practical utilization of poly(P) as ATP substitute. 相似文献
45.
Members of the nuclear factor-κB (NF-κB)/Rel family (p50, p52, p65 (RelA), RelB and c-Rel) is sequestered in the cytoplasm through its tight association with the inhibitor of NF-κB (IκB). NF-κB has been shown to function as key regulators of either cell death or survival in neurons after activation of the cells by various extracellular signals. In the study presented here, we investigated whether the selective activation of diverse NF-κB/Rel family members in HT22 cells might lead to distinct effects on glutamate-induced cell death. Exposing HT22 cells to glutamate, which blocks cystine uptake into the cells via inhibition of the glutamate-cystine antiporter, resulted in a transient activation of IκB and NF-κB/Rel and caused delayed cell death. Aspirin, which has been shown to block phosphorylation of the IκB component of the cytoplasmic NF-κB complex, significantly suppressed glutamate-induced cell death, whereas the NF-κB decoy oligonucleotide potentiated it. The inhibition of NF-κB/Rel protein expression by antisense oligonucleotides showed that p65 is involved in glutamate-mediated cell death, whereas p50 is involved in inhibitory pathways of the cell death. These findings suggest that in HT22 cells, the balance between promoting and presenting cell death to glutamate-induced oxidative stress relies on the activation of distinct NF-κB proteins. 相似文献
46.
Shinsaku Ito Tomoko Nozoye Eriko Sasaki Misaki Imai Yuh Shiwa Mari Shibata-Hatta Taichiro Ishige Kosuke Fukui Ken Ito Hiromi Nakanishi Naoko K. Nishizawa Shunsuke Yajima Tadao Asami 《PloS one》2015,10(3)
Phosphate is an essential macronutrient in plant growth and development; however, the concentration of inorganic phosphate (Pi) in soil is often suboptimal for crop performance. Accordingly, plants have developed physiological strategies to adapt to low Pi availability. Here, we report that typical Pi starvation responses in Arabidopsis are partially dependent on the strigolactone (SL) signaling pathway. SL treatment induced root hair elongation, anthocyanin accumulation, activation of acid phosphatase, and reduced plant weight, which are characteristic responses to phosphate starvation. Furthermore, the expression profile of SL-response genes correlated with the expression of genes induced by Pi starvation. These results suggest a potential overlap between SL signaling and Pi starvation signaling pathways in plants. 相似文献
47.
Kasai A Kinjo T Ishihara R Sakai I Ishimaru Y Yoshioka Y Yamamuro A Ishige K Ito Y Maeda S 《PloS one》2011,6(8):e23968
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the selective loss of motor neurons. Recent studies have implicated that chronic hypoxia and insufficient vascular endothelial growth factor (VEGF)-dependent neuroprotection may lead to the degeneration of motor neurons in ALS. Expression of apelin, an endogenous ligand for the G protein-coupled receptor APJ, is regulated by hypoxia. In addition, recent reports suggest that apelin protects neurons against glutamate-induced excitotoxicity. Here, we examined whether apelin is an endogenous neuroprotective factor using SOD1(G93A) mouse model of ALS. In mouse CNS tissues, the highest expressions of both apelin and APJ mRNAs were detected in spinal cord. APJ immunoreactivity was observed in neuronal cell bodies located in gray matter of spinal cord. Although apelin mRNA expression in the spinal cord of wild-type mice was not changed from 4 to 18 weeks age, that of SOD1(G93A) mice was reduced along with the paralytic phenotype. In addition, double mutant apelin-deficient and SOD1(G93A) displayed the disease phenotypes earlier than SOD1(G93A) littermates. Immunohistochemical observation revealed that the number of motor neurons was decreased and microglia were activated in the spinal cord of the double mutant mice, indicating that apelin deficiency pathologically accelerated the progression of ALS. Furthermore, we showed that apelin enhanced the protective effect of VEGF on H(2)O(2)-induced neuronal death in primary neurons. These results suggest that apelin/APJ system in the spinal cord has a neuroprotective effect against the pathogenesis of ALS. 相似文献
48.
49.
Gabriela Campanholle Kristen Mittelsteadt Shunsaku Nakagawa Akio Kobayashi Shuei-Liong Lin Sina A. Gharib Jay W. Heinecke Jessica A. Hamerman William A. Altemeier Jeremy S. Duffield 《PloS one》2013,8(7)
Inflammatory macrophages are abundant in kidney disease, stimulating repair, or driving chronic inflammation and fibrosis. Damage associated molecules (DAMPs), released from injured cells engage pattern recognition receptors (PRRs) on macrophages, contributing to activation. Understanding mechanisms of macrophage activation during kidney injury may lead to strategies to alleviate chronic disease. We identified Triggering-Receptor-in-Myeloid-cells (TREM)-1, a regulator of TLR signaling, as highly upregulated in kidney inflammatory macrophages and tested the roles of these receptors in macrophage activation and kidney disease. Kidney DAMPs activated macrophages in vitro, independently of TREM-1, but partially dependent on TLR-2/−4, MyD88. In two models of progressive interstitial kidney disease, TREM-1 blockade had no impact on disease or macrophage activation in vivo, but TLR-2/−4, or MyD88 deficiency was anti-inflammatory and anti-fibrotic. When MyD88 was mutated only in the myeloid lineage, however, there was no bearing on macrophage activation or disease progression. Instead, TLR-2/−4 or MyD88 deficiency reduced activation of mesenchyme lineage cells resulting in reduced inflammation and fibrosis, indicating that these pathways play dominant roles in activation of myofibroblasts but not macrophages. To conclude, TREM-1, TLR2/4 and MyD88 signaling pathways are redundant in myeloid cell activation in kidney injury, but the latter appear to regulate activation of mesenchymal cells. 相似文献
50.
Nobuyuki Suetsugu Isao Fukuzawa Shunsaku Koyama Ken’ichi Takeo Takashi Kuge 《Bioscience, biotechnology, and biochemistry》2013,77(10):2109-2110
The structures of N-glycans of total glycoproteins in royal jelly have been explored to clarify whether antigenic N-glycans occur in the famous health food. The structural feature of N-glycans linked to glycoproteins in royal jelly was first characterized by immunoblotting with an antiserum against plant complex type N-glycan and lectin-blotting with Con A and WGA. For the detail structural analysis of such N-glycans, the pyridylaminated (PA-) N-glycans were prepared from hydrazinolysates of total glycoproteins in royal jelly and each PA-sugar chain was purified by reverse-phase HPLC and size-fractionation HPLC. Each structure of the PA-sugar chains purified was identified by the combination of two-dimensional PA-sugar chain mapping, ESI-MS and MS/MS analyses, sequential exoglycosidase digestions, and 500 MHz 1H-NMR spectrometry.The immunoblotting and lectinblotting analyses preliminarily suggested the absence of antigenic N-glycan bearing β1-2 xylosyl and/or α1-3 fucosyl residue(s) and occurrence of β1-4GlcNAc residue in the insect glycoproteins.The detailed structural analysis of N-glycans of total royal jelly glycoproteins revealed that the antigenic N-glycans do not occur but the typical high mannose-type structure (Man9~4GlcNAc2) occupies 71.6% of total N-glycan, biantennary-type structures (GlcNAc2Man3GlcNAc2) 8.4%, and hybrid type structure (GlcNAc1Man4GlcNAc2) 3.0%. Although the complete structures of the remaining 17% N-glycans; C4, (HexNAc3Hex3HexNAc2: 3.0%), D2 (HexNAc2Hex5HexNAc2: 4.5%), and D3 (HexNAc3Hex4HexNAc2: 9.5%) are still obscure so far, ESI-MS analysis, exoglycosidase digestions by two kinds of β-N-acetylglucosaminidase, and WGA blotting suggested that these N-glycans might bear a β1-4 linkage N-acetylglucosaminyl residue. 相似文献