全文获取类型
收费全文 | 680篇 |
免费 | 57篇 |
出版年
2022年 | 3篇 |
2021年 | 7篇 |
2020年 | 6篇 |
2019年 | 2篇 |
2018年 | 7篇 |
2017年 | 10篇 |
2016年 | 12篇 |
2015年 | 15篇 |
2014年 | 23篇 |
2013年 | 30篇 |
2012年 | 40篇 |
2011年 | 39篇 |
2010年 | 27篇 |
2009年 | 28篇 |
2008年 | 43篇 |
2007年 | 30篇 |
2006年 | 48篇 |
2005年 | 53篇 |
2004年 | 52篇 |
2003年 | 53篇 |
2002年 | 45篇 |
2001年 | 14篇 |
2000年 | 10篇 |
1999年 | 16篇 |
1998年 | 12篇 |
1997年 | 12篇 |
1996年 | 9篇 |
1995年 | 13篇 |
1994年 | 15篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 8篇 |
1989年 | 1篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1971年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有737条查询结果,搜索用时 31 毫秒
91.
Chiaki Setoyama Yasuzo Nishina Haruhiko Tamaoki Hisashi Mizutani Ikuko Miyahara Ken Hirotsu Kiyoshi Shiga Retsu Miura 《Journal of biochemistry》2002,131(1):59-69
According to the three-dimensional structure of a porcine kidney D-amino acid oxidase-substrate (D-leucine) complex model, the G313 backbone carbonyl recognizes the substrate amino group by hydrogen bonding and the side-chain hydroxyl of T317 forms a hydrogen bond with C(2)=O of the flavin moiety of FAD [Miura et al. (1997) J. Biochem. 122, 825-833]. We have designed and expressed the G313A and T317A mutants and compared their enzymatic and spectroscopic properties with those of the wild type. The G313A mutant shows decreased activities to various D-amino acids, but the pattern of substrate specificity is different from that of the wild type. The results imply that the hydrogen bond between the G313 backbone carbonyl and the substrate amino group plays important roles in substrate recognition and in defining the substrate specificity of D-amino acid oxidase. The T317A mutant shows a decreased affinity for FAD. The steady-state kinetic measurements indicate diminished activities of T317A to substrate D-amino acids. The transient kinetic parameters measured by stopped-flow spectroscopy revealed that T317 plays key roles in stabilizing the purple intermediate, a requisite intermediate in the oxidative half-reaction, and in enhancing the release of the product from the active site, thereby optimizing the overall catalytic process of D-amino acid oxidase. 相似文献
92.
Domain structure of chondroitin sulfate E octasaccharides binding to type V collagen. 总被引:3,自引:0,他引:3
Keiichi Takagaki Hidekazu Munakata Ikuko Kakizaki Mito Iwafune Taito Itabashi Masahiko Endo 《The Journal of biological chemistry》2002,277(11):8882-8889
We demonstrated previously that chondroitin sulfate E (ChS-E) binds to type V collagen (Munakata, H., Takagaki, K., Majima, M., and Endo, M. (1999) Glycobiology 9, 1023--1027). In this study, we investigated the structure and binding of ChS-E oligosaccharides. Eleven oligosaccharides were isolated from ChS-E by gel filtration chromatography and anion-exchange high performance liquid chromatography after hydrolysis with testicular hyaluronidase. Separately, seven oligosaccharides were custom synthesized using the transglycosylation reaction of testicular hyaluronidase. Structural analysis was performed by enzymatic digestions in conjunction with high performance liquid chromatography and mass spectrometry. This library of 18 oligosaccharides was used as a source of model molecules to clarify the structural requirements for binding to type V collagen. Binding was analyzed by a biosensor based on surface plasmon resonance. The results indicated that to bind to type V collagen the oligosaccharides must have the following carbohydrate structures: 1) octasaccharide or larger in size; 2) a continuous sequence of three GlcAbeta1--3GalNAc(4S,6S) units; 3) a GlcAbeta1--3GalNAc(4S,6S) unit, GlcAbeta1--3GalNAc(4S) unit or GlcAbeta1--3GalNAc(6S) unit at the reducing terminal; 4) a GlcAbeta1--3GalNAc(4S,6S) unit at the nonreducing terminal. It is likely that these characteristic oligosaccharide sequences play key roles in cell adhesion and extracellular matrix assembly. 相似文献
93.
Inhibition of the Bacterial Cell Wall Synthesis in vitro by Enduracidin,a New Polypeptide Antibiotic
Michio Matsuhashi Ikuko Ohara Yoshihiro Yoshiyama 《Bioscience, biotechnology, and biochemistry》2013,77(1):134-137
Adenosine 5′-phosphosulfate (APS) kinase from a thermophilic bacterium, Bacillus st ear other mophilus, was purified to apparent homogeneity. The apparent molecular weight was 50 kDa, consisting of two 26-kDa subunits. The enzyme was very thermostable and lacked cysteine and methionine residues. Enzyme activity was more stimulated with Mn2 + , Zn2 +, or Co2 + than with Mg2 + and the Km for ATP and APS were 220 µM and 42 µM, respectively. 相似文献
94.
The unique capabilities of EPR spin trapping of nitric oxide based on a ferrous-dithiocarbamate spin trap have been demonstrated in a study verifying the source of the nitrogen and oxygen atoms in nitric oxide produced from activated macrophages. Spin trapping experiments were performed during nitric oxide generation from activated mouse peritoneal macrophages using the ferrous complex of N-methyl D-glucam-ine dithiocarbamate as a spin trap. When 15N-substituted arginine was given to the activated macrophages in the presence of the spin trap, a characteristic EPR spectrum of the nitric oxide spin adduct was obtained, which indicates the presence of the l5N atom in the nitric oxide molecule. The hyperfine splitting (hfs) constant of the l5N nucleus was 17.6 gauss. When l7O-containing dioxygen (55%) was supplied to the medium, an EPR spectrum consistent with the “O-substituted nitric oxide spin adduct was observed in the composite spectrum. The hfs of “O was estimated to be 2.5 gauss. The l4NO spin adduct observed after prolonged incubation in the medium which contains [l5N]L-arginine as the only extracellular source of arginine demonstrates that arginine is recycled through its metabolite in activated macrophages. 相似文献
95.
96.
Ikuko Fujisaki Kenneth G. Rice Leonard G. Pearlstine Frank J. Mazzotti 《Hydrobiologia》2009,635(1):329-338
Feeding opportunities of American alligators (Alligator mississippiensis) in freshwater wetlands in south Florida are closely linked to hydrologic conditions. In the Everglades, seasonally and annually
fluctuating surface water levels affect populations of aquatic organisms that alligators consume. Since prey becomes more
concentrated when water depth decreases, we hypothesized an inverse relationship between body condition and water depth in
the Everglades. On average, condition of adult alligators in the dry season was significantly higher than in the wet season,
but this was not the case for juveniles/subadults. The correlation between body condition and measured water depth at capture
locations was weak; however, there was a significant negative correlation between the condition and predicted water depth
prior to capture for all animals except for spring juveniles/subadults which had a weak positive condition–water depth relationship.
Overall, a relatively strong inverse correlation occurred at 10–49 days prior to the capture day, suggesting that current
body condition of alligators may depend on feeding opportunities during that period. Fitted regression of body condition on
water depth (mean depth of 10 days when condition-water depth correlation was greatest) resulted in a significantly negative
slope, except for spring adult females and spring juveniles/subadults for which slopes were not significantly different from
zero. Our results imply that water management practices may be critical for alligators in the Everglades since water depth
can affect animal condition in a relatively short period of time. 相似文献
97.
Yasuko Koumoto Ryuji Tsugeki Tomoo Shimada Hitoshi Mori Maki Kondo Ikuko Hara-Nishimura Mikio Nishimura 《The Plant journal : for cell and molecular biology》1996,10(6):1119-1125
Chaperonin (Cpn) is one of the molecular chaperones. Cpn10 is a co-factor of Cpn60, which regulates Cpn60-mediated protein folding. It is known that Cpn10 is located in mitochondria and chloroplasts in plant cells. The Escherichia coli homologue of Cpn10 is called GroES. A cDNA for the Cpn10 homologue was isolated from Arabidopsis thaliana by functional complementation of the E. coli groES mutant. The cDNA was 647 bp long and encoded a polypeptide of 98 amino acids. The deduced amino acid sequence showed approximately 50% identity to mammalian mitochondrial Cpn10s and 30% identity to GroES. A Northern blot analysis revealed that the mRNA for the Cpn10 homologue was expressed uniformly in various organs and was markedly induced by heat-shock treatment. The Cpn10 homologue was constitutively expressed in transgenic tobaccos. Immunogold and immunoblot analyses following the subcellular fractionation of leaves from transgenic tobaccos revealed that the Cpn10 homologue was localized in mitochondria and accumulated at a high level in transgenic tobaccos. 相似文献
98.
Summary We describe a genetic polymorphism of a human cellular polypeptide with mol. wt. 100,000, detected in peripheral blood lymphocytes by high resolution two-dimensional electrophoresis. Three different electrophoretic types (1-1, 2-1, and 2-2) of the polypeptide have been identified. Family and population studies indicate that the three phenotypes of the polypeptide are determined by two common alleles at a single autosomal locus. The polypeptide occurs in the cytosol and is one of the abundant polypeptides of B-lymphoblastoid cells, T-lymphoblastoid cells, fibroblasts, and HeLa cells. The data indicate that the cytosol polypeptide with mol.wt. 100,000 shows a genetic polymorphism determined by aew autosomal locus. It is proposed that the polypeptide and its locus be temporarily designated cytosol 100k polypeptide (C100k polypeptide) and C100P, respectively. In a Japanese population, the gene frequencies of C100P
1 and C100P
2 were 0.907 and 0.093, respectively. 相似文献
99.
Koichi Kusuhara Akira Takabayashi Kohji Ueda Yasufumi Hidaka Ikuko Minamishima Hiromichi Take Katsuyoshi Fujioka Shosuke Imai Toyoro Osato 《Microbiology and immunology》1997,41(4):309-312
In order to evaluate the possibility of Epstein-Barr virus (EBV) and human herpesvirus 6 (HHV-6) transmission via breast milk, a total of 331 serum specimens collected from bottle-fed and breast-fed children and their mothers, in 2 endemic areas of human T-cell lymphotropic virus type I (HTLV-I) in Japan, were assayed for antibodies to EBV and HHV-6. The seroprevalences of EBV and HHV-6 were over 95% both in the mothers of bottle-fed children and in those of breast-fed children. The seroprevalence of EBV at 12–23 months of age was 54.5% (36/66) and 55.8% (24/43) in breast-fed children and bottle-fed children, respectively. The seroprevalence of HHV-6 at 12–23 months of age was 90.9% (60/66) and 93.0% (40/43) in breast-fed children and bottle-fed children, respectively. No difference was observed between the seroprevalences of EBV and HHV-6 in breast-fed and bottle-fed children at 12–23 months of age. Our seroepidemiologic data indicate that breast milk is not a significant source of early EBV or HHV-6 infection in infancy. 相似文献
100.
Minami Yoshiko; Takao Hiroyasu; Kanafuji Takeo; Miura Kazuo; Kondo Maki; Hara-Nishimura Ikuko; Nishimura Mikio; Matsubara Hiroshi 《Plant & cell physiology》1997,38(9):1069-1074
rß-Glucosidase of indigo plant (Polygonum tinctorium)has a high substrate specificity for indican (indoxyl rß-D-gIu-coside).To examine the localization of this rß-glucosidase,we fractionated the cells of the leaves and analysed them im-munocytochemically.Immunoelectron micrographs with specific antibodies againstthe rßglucosidase clearly showed that the rß-glucosidasewas localized in the stroma of the chloroplasts in mesophyllcells, but not in the thylakoid membrane. Chloroplasts wereisolated from the crude ho-mogenate of the fresh leaves by Percolldensity gradient centrifugation and then subjected to suborganellarfrac-tionation. rßGlucosidase activity was specificallydetected in the stromal fraction, but not in the thylakoid membrane.This was also supported by the result of an immunoblot of thefractions with anti-rßglucosidase antibodies. Therß-gIu-cosidase was immunocytochemically localizedin the chloroplasts of mesophyll cells, but not in any chloroplastsin marginal cells of the vascular bundle or epidermal cells;ribulose 1,5-bisphosphate carboxylase (Rubisco), a typical stromalprotein, was observed in all chloroplasts in these cells. Theseresults suggest that rß-glucosidase is tissue specificin its expression in the leaves of the indigo plant. (Received April 14, 1997; Accepted July 10, 1997) 相似文献