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71.
We have previously shown that in Dictyostelium cells a 32 kDa protein is rapidly and completely dephosphorylated in response to starvation that is essential for the initiation of differentiation (Akiyama & Maeda 1992). In the present work, this phosphoprotein was identified as a homologue (Dd-RPS6) of ribosomal protein S6 (RPS6) that is an essential member for protein synthesis. As expected, Dd-RPS6 seems to be absolutely required for cell survival, because we failed to obtain antisense-RNA mediated cells as well as Dd-rps6-null cells by homologous recombination in spite of many trials. In many kinds of cell lines, RPS6 is known to be located in the nucleus and cytosol, but Dd-RPS6 is predominantly located in the cell cortex with cytoskeletons, and in the contractile ring of just-dividing cells. In this connection, the overexpression of Dd-RPS6 greatly impairs cytokinesis during axenic shake-cultures in growth medium, resulting in the formation of multinucleate cells. Much severe impairment of cytokinesis was observed when Dd-RPS6-overexpressing cells (Dd-RPS6(OE) cells) were incubated on a living Escherichia coli lawn. The initiation of differentiation triggered by starvation was also delayed in Dd-RPS6(OE) cells. In addition, Dd-RPS6(OE) cells exhibit defective differentiation into prespore cells and spores during late development. Thus, it is likely that the proper expression of Dd-RPS6 may be of importance for the normal progression of late differentiation as well as for the initiation of differentiation. 相似文献
72.
Guianfranco Mazzei Ryohei Ikegami Nona Abolhassani Naoki Haruyama Kunihiko Sakumi Takashi Saito Takaomi C. Saido Yusaku Nakabeppu 《Aging cell》2021,20(8)
Insulin resistance and diabetes mellitus are major risk factors for Alzheimer''s disease (AD), and studies with transgenic mouse models of AD have provided supportive evidence with some controversies. To overcome potential artifacts derived from transgenes, we used a knock‐in mouse model, AppNL−F/NL−F , which accumulates Aβ plaques from 6 months of age and shows mild cognitive impairment at 18 months of age, without the overproduction of APP. In the present study, 6‐month‐old male AppNL−F/NL−F and wild‐type mice were fed a regular or high‐fat diet (HFD) for 12 months. HFD treatment caused obesity and impaired glucose tolerance (i.e., T2DM conditions) in both wild‐type and AppNL−F/NL−F mice, but only the latter animals exhibited an impaired cognitive function accompanied by marked increases in both Aβ deposition and microgliosis as well as insulin resistance in the hippocampus. Furthermore, HFD‐fed AppNL−F/NL−F mice exhibited a significant decrease in volume of the granule cell layer in the dentate gyrus and an increased accumulation of 8‐oxoguanine, an oxidized guanine base, in the nuclei of granule cells. Gene expression profiling by microarrays revealed that the populations of the cell types in hippocampus were not significantly different between the two mouse lines, regardless of the diet. In addition, HFD treatment decreased the expression of the Aβ binding protein transthyretin (TTR) in AppNL−F/NL−F mice, suggesting that the depletion of TTR underlies the increased Aβ deposition in the hippocampus of HFD‐fed AppNL−F/NL−F mice. 相似文献
73.
Tohsato Y Baba T Mazaki Y Ito M Wanner BL Mori H 《Journal of bioinformatics and computational biology》2010,8(Z1):83-99
Systematic studies have revealed that single gene deletions often display little phenotypic effects under laboratory conditions and that in many cases gene dispensability depends on the experimental conditions. To elucidate the environmental dependency of genes, we analyzed the effects of gene deletions by Phenotype MicroArray? (PM), a system for quantitative screening of thousands of phenotypes in a high-throughput manner. Here, we proposed a new statistical approach to minimize error inherent in measurements of low respiration rates and find which mutants showed significant phenotypic changes in comparison to the wild-type. We show analyzing results from comprehensive PM assays of 298 single-gene knockout mutants in the Keio collection and two additional mutants under 1,920 different conditions. We focused on isozymes of these genes as simple duplications and analyzed correlations between phenotype changes and protein expression levels. Our results revealed divergence of the environmental dependency of the gene among the knockout genes and have also given some insights into possibilities of alternative pathways and availabilities of information on protein synthesis patterns to classify or predict functions of target genes from systematic phenotype screening. 相似文献
74.
Yusaku Uga Kazutoshi Okuno Masahiro Yano 《Molecular breeding : new strategies in plant improvement》2010,26(3):533-538
The stele (root vascular cylinder) in plants plays an important role in the transport of water and nutrients from the root
to the shoot. A quantitative trait locus (QTL) on rice chromosome 9 that controls stele transversal area (STA) was previously
detected in an F3 mapping population derived from a cross between the lowland cultivar ‘IR64’, with a small STA, and the upland cultivar ‘Kinandang
Patong’, with a large STA. To identify the gene(s) underlying this QTL, we undertook fine mapping of the locus. We screened
eight plants from BC2F3 lines in which recombination occurred near the QTL. Progeny testing of BC2F4 plants was used to determine the genotype classes for the QTL in each BC2F3 line. Accordingly, the STA QTL Sta1 (Stele Transversal Area 1) was mapped between the InDel markers ID07_12 and ID07_14. A candidate genomic region for Sta1 was defined more precisely between markers RM566 and RM24334, which delimit a 359-kb interval in the reference cultivar ‘Nipponbare’.
A line homozygous for the ‘Kinandang Patong’ allele of Sta1 had an STA approximately 28.4% larger than that of ‘IR64’. However, Sta1 did not influence maximum or total root length, suggesting that this QTL specifically controls STA. 相似文献
75.
76.
OBJECTIVE: To clarify the cytologic diagnostic problems of uterine sarcomas and the differential properties between pure sarcomas and carcinosarcomas. STUDY DESIGN: Four leiomyosarcomas and 21 carcinosarcomas (homologous and heterologous) treated at the Saitama Cancer Center from 1991 to 2000 were analyzed macroscopically and microscopically. RESULTS: Of 4 leiomyosarcomas, 3 were intramuscular, localized type, with a negative diagnosis for sarcoma. Of 21 carcinosarcomas, 7 were exophytic type with little necrosis (B-1), 5 were exophytic type with marked necrosis (B-2), 6 were exophytic type with a small sarcomatous component (B-3), and 3 were endophytic type (B-4). All endometrial smears were positive for sarcoma in B-1, whereas 5 of 14 (36%) were positive in the latter 3 types (B-2, 3 and 4). CONCLUSION: In pure leiomyosarcomas, the sarcomatous portions are usually covered with normal endometrium. In carcinosarcomas, sarcomatous component is relatively limited in some cases and frequently covered with marked necrosis or carcinomatous tissue. These pathologically specific findings should make cytologic diagnosis difficult in uterine sarcomas. 相似文献
77.
Medium-chain acyl-coenzyme A (CoA) esters are key metabolites in lipid metabolism. Liquid chromatography-electrospray ionization mass spectrometry analysis of medium-chain acyl-CoA esters is described. Eight medium-chain acyl-CoA esters were well separated on a C(8)-MS reversed-phase column using a linear gradient of ammonium acetate buffer (pH 5.3)-acetonitrile. The positive-ion mass spectra of all the saturated and unsaturated medium-chain acyl-CoA esters gave dominant [M+H](+) ions, whereas their negative-ion mass spectra showed abundant [M-H](-) and [M-2H](2-) ions. The positive-ion mode of operation was slightly less sensitive than the negative-ion detection mode. Five medium-chain acyl-CoA esters of C(6:0), C(8:0), C(8:1), C(10:0), and C(10:1) in liver, heart, kidney, and brain from the mouse were identified. The predominant acyl-CoA peaks were C(6:0), C(8:0), and C(10:0). Small amounts of medium-chain acyl-CoAs of C(8:1) and C(10:1) were detected only in heart and kidney. The analytical method is very useful for the analysis of medium-chain acyl-CoA esters in the tissues. 相似文献
78.
Novel two iridium terphenyl complexes were prepared and their structures were characterized crystallographically. The reaction of [Ir(cod)2]BF4 with p-terphenyl (p-tp) in CH2Cl2 was carried out to afford dinuclear Ir(I) complex {[Ir2(p-tp)(cod)2](BF4)2 · 2CH2Cl2}3 (cod=1,5-cyclooctadiene) (1 · 2CH2Cl2), whereas the reaction of the intermediate [Ir(η5-C5Me5)(Me2CO)3]3+ in Me2CO with m-terphenyl (m-tp) was done to provide mononuclear Ir(III) complex [Ir(m-tp)(η5-C5Me5)](BF4)2 (2). In complex 1 · 2CH2Cl2, two Ir atoms are η6-coordinated to both sides of terminal benzene rings from the upper and lower sides in the p-tp ligand, while one Ir atom is η6-coordinated to one side of the terminal benzene ring in the m-tp ligand in complex 2. Each crystal structure describes the first coordination mode found in metal complexes with the m- and p-tp ligands. 相似文献
79.
We isolated a mouse cDNA encoding APEX2 protein and demonstrated that APEX2 binds to PCNA. The level of Apex2 mRNA was high in the thymus, bone marrow, spleen, and kidney in adult mice. Apex2 consists of six exons and is flanked on the 3' end by Alas2 on X chromosome 63.0. Furthermore, Apex2 is flanked on the 5' end by a novel gene with a 106-bp intergenic sequence. We disrupted Apex2 in embryonic stem cells derived from a male mouse, and a 55-kDa APEX2 protein was detected in the nuclei of Apex2(+) but not Apex2-disrupted cells. Immunoelectron microscopy revealed that APEX2 is also localized in the mitochondria of Apex2(+) cells. In serum-stimulated BALB/c 3T3 cells, the level of Apex2 mRNA was transiently increased and the level of APEX2 reached a maximum in the late S phase, thus indicating that APEX2 may participate in postreplicative base excision repair. 相似文献
80.
Yusaku Suenaga Kouzou KitamuraTakayoshi Kuroda-Sowa Masahiko MaekawaMegumu Munakata 《Inorganica chimica acta》2002,328(1):105-110
Silver(I) complexes of hexakis(tolylsulfanyl)benzene (htsb), [Ag(htsb)](PF6) (1), have been prepared and their molecular structures were determined by X-ray crystallography. In 1, the silver ion prefers a square planar coordination geometry comprized of four S atoms from two different htsb molecules and producing a zigzag chain structure of AgS in the silver coordination polymer. Based on the thermo-gravimetry analysis results, two tolylsulfanyl groups were easily eliminated at approximately 211 °C. However, [Ag(htsb)(2-butanone)] (PF6) (2), which were obtained by the reactions in different solvents, showed a different colors and thermal degradation behaviors. 相似文献