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51.
A Gram-negative bacterium was previously isolated from an oil field in Shizuoka, Japan, and designated strain HD-1. Here we have performed detailed characterization of the strain, and have found that it represents a novel genus. The 16S rRNA sequence of strain HD-1 displayed highest similarity to various uncultured species (86.7-99.7%), along with 86.2-88.2% similarity to sequences from Azospirillum, Methylobacterium, Rhizobium, and Hyphomicrobium, all members of the alpha-Proteobacteria. Phylogenetic analysis revealed that HD-1 represented a deep-branched lineage among the alpha-Proteobacteria. DNA-DNA hybridization analysis with Azospirillum lipoferum and Hyphomicrobium vulgare revealed low levels of similarity among the strains. We further examined the biochemical properties of the strain under aerobic conditions. Among carbon sources, ethanol, n-propanol, n-butanol, and n-tetradecanol were the most preferred, while acetate, propionate, and pyruvate also supported high levels of growth. The strain could also grow on aromatic compounds such as toluene, benzene and phenol, and aliphatic hydrocarbons such as n-octane and n-tetradecane. In contrast, glycerol and various sugars, including glucose, fructose, maltose, and lactose, failed to support growth of HD-1. Under an anaerobic gas phase with butanol as the carbon source, little increase in cell weight was observed with the addition of several possible electron acceptors. As strain HD-1 represents a novel genus in the alpha-Proteobacteria, we designated the strain as Oleomonas sagaranensis gen. nov., sp. nov., strain HD-1. 相似文献
52.
Iwai M Tanaka S Mori T Harada Y Muramatsu A Morikawa T Kashima K Fushiki S 《Cell biology and toxicology》2002,18(3):147-156
The fetal mouse liver tissues in our organotypic slice culture were spread and flattened for at least 3 weeks; small, round
cells were distributed in the center and polygonal cells were seen in the periphery. Ultrastructurally, polygonal cells showed
abundant rough endoplasmic reticulum and mitochondria. They expressed albumin (ALB) and α-fetoprotein (AFP) for at least 3
weeks, and Cx32-immunoreactivity was also seen in a plaque on the cells. Many proliferating cell nuclear antigen (PCNA)-positive
cells were observed at the periphery, and there were scattered CK-19-positive cells.
The spreading of the fetal liver tissue in organotypic slice culture was reduced in medium containing sodium butyrate (SB).
The expression of ALB was well maintained in polyglonal cells of the SB(+) group 3 weeks after culture and AFP-immunoreactivity
was decreased in the SB(+) group. The concentration of ALB in the medium was significantly higher in the SB(+) than in the
SB(-) group. CK-19-positive cells in the SB(+) group were increased in number more than those in the SB(-) group. PCNA-positive
cells were less numerous in the SB(+) group, and Cx32-positive plaques were increased. SB can help immature hepatocytes to
differentiate into the mature type and the cholangiocytic lineage, reducing their proliferation.
These findings suggest that parenchymal cells in our organotypic slice culture of the fetal mouse liver can maintain structure
and function as in vivo for the long term, and SB is shown to be a differentiation inducer of parenchymal cells in the slice culture.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
53.
Cleavage of a DNA-RNA-DNA/DNA chimeric substrate containing a single ribonucleotide at the DNA-RNA junction with prokaryotic RNases HII 总被引:1,自引:0,他引:1
We have analyzed the cleavage specificities of various prokaryotic Type 2 ribonucleases H (RNases H) on chimeric DNA-RNA-DNA/DNA substrates containing one to four ribonucleotides. RNases HII from Bacillus subtilis and Thermococcus kodakaraensis cleaved all of these substrates to produce a DNA segment with a 5'-monoribonucleotide. Consequently, these enzymes cleaved even the chimeric substrate containing a single ribonucleotide at the DNA-RNA junction (5'-side of the single ribonucleotide). In contrast, Escherichia coli RNase HI and B. subtilis RNase HIII did not cleave the chimeric substrate containing a single ribonucleotide. These results suggest that bacterial and archaeal RNases HII are involved in excision of a single ribonucleotide misincorporated into DNA. 相似文献
54.
Yamada K Miyata T Tsuchiya D Oyama T Fujiwara Y Ohnishi T Iwasaki H Shinagawa H Ariyoshi M Mayanagi K Morikawa K 《Molecular cell》2002,10(3):671-681
We present the X-ray structure of the RuvA-RuvB complex, which plays a crucial role in ATP-dependent branch migration. Two RuvA tetramers form the symmetric and closed octameric shell, where four RuvA domain IIIs spring out in the two opposite directions to be individually caught by a single RuvB. The binding of domain III deforms the protruding beta hairpin in the N-terminal domain of RuvB and thereby appears to induce a functional and less symmetric RuvB hexameric ring. The model of the RuvA-RuvB junction DNA ternary complex, constructed by fitting the X-ray structure into the averaged electron microscopic images of the RuvA-RuvB junction, appears to be more compatible with the branch migration mode of a fixed RuvA-RuvB interaction than with a rotational interaction mode. 相似文献
55.
Roongsawang N Thaniyavarn J Thaniyavarn S Kameyama T Haruki M Imanaka T Morikawa M Kanaya S 《Extremophiles : life under extreme conditions》2002,6(6):499-506
Twenty-three halotolerant and biosurfactant producing strains were collected from salty conditions in central Thailand. One of the strains designated BBK-1 produced the biosurfactants with the highest activity. BBK-1 was isolated from fermented foods and was identified as B. subtilis based on its physiological characteristics and 16S rRNA gene sequence. We show that the strain grows in media containing NaCl up to 16% (w/v) and produces biosurfactants in NaCl up to 8%. We found that B. subtilis BBK-1 produces three kinds of surface-active lipopeptides simultaneously. By their respective molecular weights and amino acid compositions, it is indicated that these lipopeptides are bacillomycin L, plipastatin, and surfactin. In order to analyze the production mechanism of lipopeptides further in the strain, a generally important biosynthetic gene encoding 4'-phosphopantetheinyl transferase was cloned and sequenced. The gene existed in a single copy in the genome and the deduced amino acid sequence was almost identical to that of Lpa-14 from B. subtilis strain RB14, which co-produces iturin A and surfactin. 相似文献
56.
Yoshikawa M Morikawa T Matsuda H Tanabe G Muraoka O 《Bioorganic & medicinal chemistry》2002,10(5):1547-1554
A most potent alpha-glucosidase inhibitor named salacinol has been isolated from an antidiabetic Ayurvedic traditional medicine, Salacia reticulata WIGHT, through bioassay-guided separation. The absolute stereostructure of salacinol was determined on the basis of chemical and physicochemical evidence, which included the alkaline degradation of salacinol to 1-deoxy-4-thio-D-arabinofuranose and the X-ray crystallographic analysis, to be the unique spiro-like configuration of the inner salt comprised of 1-deoxy-4-thio-D-arabinofuranosyl sulfonium cation and 1'-deoxy-D-erythrosyl-3'-sulfate anion. Salacinol showed potent inhibitory activities on several alpha-glucosidases, such as maltase, sucrase, and isomaltase, and the inhibitory effects on serum glucose levels in maltose- and sucrose-loaded rats (in vivo) were found to be more potent than that of acarbose, a commercial alpha-glucosidase inhibitor. 相似文献
57.
58.
59.
Nosaka T Morita S Kitamura H Nakajima H Shibata F Morikawa Y Kataoka Y Ebihara Y Kawashima T Itoh T Ozaki K Senba E Tsuji K Makishima F Yoshida N Kitamura T 《Molecular and cellular biology》2003,23(8):2969-2980
Dorsoventral patterning depends on the local concentrations of the morphogens. Twisted gastrulation (TSG) regulates the extracellular availability of a mesoderm inducer, bone morphogenetic protein 4 (BMP-4). However, TSG function in vivo is still unclear. We isolated a TSG cDNA as a secreted molecule from the mouse aorta-gonad-mesonephros region. Here we show that TSG-deficient mice were born healthy, but more than half of the neonatal pups showed severe growth retardation shortly after birth and displayed dwarfism with delayed endochondral ossification and lymphopenia, followed by death within a month. TSG-deficient thymus was atrophic, and phosphorylation of SMAD1 was augmented in the thymocytes, suggesting enhanced BMP-4 signaling in the thymus. Since BMP-4 promotes skeletogenesis and inhibits thymus development, our findings suggest that TSG acts as both a BMP-4 agonist in skeletogenesis and a BMP-4 antagonist in T-cell development. Although lymphopenia in TSG-deficient mice would partly be ascribed to systemic effects of runtiness and wasting, our findings may also provide a clue for understanding the pathogenesis of human dwarfism with combined immunodeficiency. 相似文献
60.
Shimizu M Hiroaki H Kohda D Hosoya T Akiyama-Oda Y Hotta Y Morita EH Morikawa K 《Protein engineering》2003,16(4):247-254
Drosophila GCM (glial cell missing) is a novel DNA-binding protein that determines the fate of glial precursors from the neural default to glia. The GCM protein contains the functional domain that is essential for recognition of the upstream sequence of the repo gene. In the DNA-binding region of this GCM protein, there is a cysteine-rich region with which divalent metal ions such as Zn(2+) must bind and other proteins belonging to the GCM family have a corresponding region. To obtain a more detailed insight into the structural and functional features of this DNA-binding region, we have determined the minimal DNA-binding domain and obtained inductively coupled plasma atomic emission spectra and (1)H-(15)N, (1)H-(15)N-(13)C and (113)Cd(2+) NMR spectra, with or without its specific DNA molecule. Considering the results, it was concluded that the minimal DNA-binding domain includes two Zn(2+)-binding sites, one of which is adjacent to the interface for DNA binding. Systematic mutational analyses of the conserved cysteine residues in the minimal DNA-binding domain revealed that one Zn(2+)-binding site is indispensable for stabilization of the higher order structure of this DNA-binding domain, but that the other is not. 相似文献